The stream page was broken - showing only annotations from the group
that was focused the last time the user was using the sidebar.

Fix it to show annotations from all groups.

When switching between groups (and reloading the angular view more
generally) drafts are persisted. But we don't want to display drafts for
groups other than the one currently focused, because otherwise we'll end
up in a position where we can see annotations published to another
group.

This commit adds an additional condition to
`ThreadController#shouldShow`: if the thread root annotation has a group
set, and that group doesn't match the focused group id, then the thread
will be hidden.

Always focus the Public / __world__ group if the groups feature is
toggled off.

When the groups feature was off a group other than Public might have
been retrieved from the browser's localStorage (this could only happen
if the groups feature had previously been on for the user) and the wrong
annotations would be shown in the sidebar.

Replace `isSidebar`, `isEmbedded`, `annotation-embedded`, `annotationEmbedded`
and `embedded` with a single `isSidebar` variable.

- Rename `isEmbedded` in AppController to `isSidebar`.

- Rename `embedded` in AnnotationController to `isSidebar`, it just passes the
value of `AppController`'s `isSidebar` into `annotation.html`.

- Rename the `annotation-embedded`/`annotationEmbedded` variable that is used
to pass `isSidebar` (was `isEmbedded`) into `AnnotationController`,
rename it to `is-sidebar` / `isSidebar`.

- Delete the duplicate `isSidebar` variable from `WidgetController`'s scope,
`WidgetController`'s templates can simply access `AppController`'s `isSidebar`
from the scope.

Note that there's another variable, `isStream`, that's actually true when we're
either in the sidebar or on the stream page, but not when we're on individual
annotation pages. This is used to show/hide the
"Sorted by newest, oldest, location" menu which appears in the sidebar or
stream but not on individual annotation pages (the "location" option in this
menu only appears when in the sidebar not on the stream).

This commit leaves the `isStream` variable alone.

So the `isSidebar` variable is now used to show/hide the following elements:

- The share dialog (share this page on twitter etc) is shown in the top bar,
only when in the sidebar (and not on the `/stream` page or on individual
annotation pages).

- The group list dropdown menu, shown in the top bar only when in the sidebar.

- The "location" entry in the sort menu (sorted by newest, oldest, location)
shown only when in the sidebar.

- The "citation" on annotations that says which page was annotated
(the 'on "Example Document" (example.com)' in the annotation's title),
is shown only when _not_ in the sidebar.

When a user clicks on a group name in the "scope selector" dropdown
menu, we want to filter the visible annotations by group. This commit
implements a rather inefficient but functional approach to this, simply
reloading the angular view.

In addition, we make sure that the initial annotation load includes a
filter on the currently-focused group, and we discard non-focused-group
annotations coming in over the websocket.

Avoid String.prototype.startsWith() for compatibility Safari and IE

Links to source document URIs were broken under Safari <= 8 and
other browsers as well due to reliance on the
String.prototype.startsWith() API

This issue went unnoticed in Karma/PhantomJS tests because
Karma was primed with the complete set of polyfills from
the js-polyfills library, including many (all?) ES6 polyfills.

This same set of polyfills was_not_ used in the browser build however.

This commit fixes the original issue by using 'indexOf()' instead of
'startsWith()' and reduces the likelihood of such problems going
unnoticed during testing by using a much more minimal set of polyfills
under PhantomJS.

The alternative approach would be to go in the opposite direction
and polyfill any ES6 APIs in the browser. However, we need to be
careful about code bloat, so the approach taken here is the more
conservative option.

Fixes #2568

Show filenames of local documents with titles

When the annotated document is a local (file://) document and it has a
title, then show the filename in place of the domain on the annotation
card. For example:

  seanh on "Document Title" (filename.pdf)

In cases where the document has no title then the filename would already
have been used in place of "Document Title" so don't repeat it in
(...)'s.

For remote documents the domain name is shown in (...)'s instead and the
document title is hyperlinked so the people can see the full URL by
hovering over the link.

Consolidate thread show/hide logic into ThreadController

This template conditional is notorious for accumulating extra terms, so
this commit rolls it into ThreadController where it can be more easily
tested.

T89 combined scope save btn

When changing permissions via the dropdown menu,
the changed permissions were applied to the _domain model_
representing the saved annotation instead of the _view model_
representing the current annotation being edited.

The change to the domain model triggered a reset of the view
model via AnnotationController.render(), losing any unsaved edits.

This commit makes AnnotationController.setPrivacy() apply permissions
changes to the view model in the same way as other edits in the
annotation view. These then only take effect when the 'Post to'
button is clicked.

Fixes #2567

Instead of patching the upstream UI Bootstrap build, add a wrapper around
it which stubs the $templateRequest service and wraps the Angular 1.2x implementation
of $animate.(add|remove)Class with one which returns a Promise as
UI Bootstrap expects.

When the app is upgraded to Angular 1.3x+, the 'ui-bootstrap-custom' module can just
be removed.

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When transforming old-style comments, handle null targets

Make activation created_by/valid_until fields nullable

Fix a bug where canceling changes did not reset the text

AnnotationController.revert() reverted changes to the
annotation in the editor by copying across properties
from the saved annotation to the draft.

Any properties which were _added_ in the draft but not
set in the saved version, such as the text when the text
is empty, were not reverted.

Fixes #2561

Add the updated group icon and update the icomoon font.
Also simplify the instructions for updating the icomoon font.

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In Chrome, clicks on elements inside a disabled <button>
will not invoke the <button>'s "click" event listeners
but they will propagate through the button and invoke parent
element's click handlers. In Firefox however, the click
event is not propagated.

The fix here is to install the click handler for the main
part of a dropdown button on the <button> itself, rather than
the container <div> which holds the main button and
the dropdown arrow.

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The spacing was lost when the cancel button was moved
into the <publish-annotation-btn> directive.

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Fix email notifications

Add guidelines for writing model code and db migrations

Update instructions for running front-end tests.

Make auth.effective_principals do what it says

 * Use cancel button with a thin circle outline

 * Change normal and hover colors to light/dark grey as
   per discussion on the card.

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Automatically convert URLs in annotation text to links

Add a cancel button with a thin circle outline which
matches the design.

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This text has been obsoleted by the new 'Post to XXX' design
which makes it clearer who new annotations will be visible to.

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Only URLs with a scheme or beginning with 'www.' are processed.

Fixes #2505

Instead of passing a full object of attributes to
util.createDirective() at the start of each test, render
a default instance in beforeEach() and then just relink
the element with the changes for a specific test.

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When false, both the dropdown menu and the post button are disabled.

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