T87 - Improve group scope dropdown ui

For IE 10 and Safari < 9 support, use prefixed flexbox.

For now, this duplicates the flexbox declarations as is
done in topbar.scss. I will look into using autoprefixer for
this separately.

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cf410d0 broke standalone annotation pages by changing
`threadRoot.children` from an array into a thread container.
Unsurprisingly, `children` is supposed to be an array.

 * Use the singular 'groupList' everywhere

 * Simplify the logic for stopping click propagation
   when toggling the selected group

 * Remove underscore prefix for Controller classes as per the PR
   discussion.

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Fix detection of PDF URIs

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*N.B.* This does not fix the underlying problem, but it does make it
possible to deploy the existing codebase without breaking everything in
production.

70c9b9b broke a number of features of the h client that were toggled on
for PDF documents, by renaming the Annotator PDF plugin from
`Annotator.Plugin.PDF` to `Annotator.Plugin.Pdf`.

While it's certainly an ugly side-effect of a straightforward rename,
the problem is that `Guest#getDocumentInfo` (to pick one example) used
`@plugins.PDF?` to determine whether to use the PDF metadata
(provided by the PDF.js `PDFViewerApplication`).

In the absence of PDF metadata, `getDocumentInfo` falls back to using
`window.location.href`, which explains the behaviour identified
in #2506.

Fixes #2506.

Add a test for the controller part of the <groups-list> directive.

We have a couple of different patterns for testing directive
controllers in the code, the approach taken here follows the privacy
dropdown's directive in simply exporting the controller's constructor
as a 'private' export and referencing it directly in the test.

 * Rename the exports in the 'directive/privacy' module for consistency

 * Restructure the 'New group' item to make icon
   and label align with the items above it

 * Make the whole 'New group' section clickable

 * Make 'New group' icon bold for visual consistency
   with other icons

 * Use the prerendered group URL from the API instead
   of generating it locally

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 * Use an element directive for <group-list> for
   consistency with the <privacy> directive and because
   the directive has its own template.

 * Use flexbox for easier layout of items in the groups
   dropdown list.

 * Update the hover and selection states of items in the dropdown
   list as per the mocks.

 * Add descriptive titles to all links in the list

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 * Use the brand color for hovered items,
   including selected items.

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Use nesting for readability.

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Use a light grey background.

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Add make target to run karma tests with auto-watch enabled

Show orphan annotations with a notice

The positions of the anchors are no longer needed.

This provides a convenient way to start Karma tests and auto-run
them when test files are changed.

Because the test files are incorporated into a Browserify bundle
by karma-browserify which watches files for changes via watchify(),
we can turn off Karma's own watching of the test files.

This fixes a problem where changing a test spec file would result
in Karma running all the tests twice, once after the test spec file
changed and then again afterwards due to the browserify bundle
being updated a second or two after the test spec file changes.

DRY in .editorconfig and add SCSS settings

cf410d0 broke thread sorting by interfering with the (admittedly
arcane) sort apparatus.

There is a scope.watch in the AppController which is responsible for
filling the `predicate` field of the `sort` object when the `name` field
changes. In order for this to work, the controllers in child scopes
(namely StreamController or WidgetController) need to modify the `name`
property of the `sort` object in the parent scope, via prototypal
inheritance, rather than replacing the entire `sort` object.

Clean up socket, threading, mapper with routing

Move all the logic required to set up a clean environment for the
client views into the dependency resolution mechanism of ngRoute.

The annotation mapper gains an unloadAnnotations method to make the
isolated code cleaner.

Use angular-websocket to remove the need for our own socket class.

The AppController becomes much more sane.

Merge pull request #2475 from hypothesis/oWe60V8v-signal-when-there-are-public-annotations-on-a-page

Signal when there are public annotations on a page in the Chrome extension icon

I was getting multiple test fails on Travis that were not failing
locally, due to differences between my local Sinon and Travis's. Pinning
Sinon to the latest version fixes this.

Add a simple user info dashboard for admins

Allows administrators to look up user information from the
administration panel.

Close #1916

Installation docs corrections

Split host / sidebar and clean up plugin loading

Improve factoring of search/filtering

Refactor Pyramid routing and view configuration

Lenient search

More variable substitution becomes available.

Keep weaning off jQuery.

Fix issues with Object.getOwnPropertyNames under PhantomJS.

Let each frame just emit the event locally and invoke its own local
method in response to the RPC call. The widget, acting as the hub
of the communication bridge, stops infinite RPC loop by only
propagating the call when it would change the state.