Remove unnecessary code for checking type of `annotation.references` field

Bugfix: whole page annotation highlights

We now have much more control over how fields are rendered to JSON on
the server and as a result, this field is always either unset or an
array of strings.

Repurposed About panel for Help

Underline links in the Help panel text to make them standout and make
the `/docs/help` URL work when the app is served from browser extensions
extension by prefixing it with the service URL.

Also remove extraneous spaces from around the 'Send us a message' text.

Highlight the specific reply on standalone annotation pages for replies

Reimplement NIPSA operations using NipsaService

Record approximate time-in-queue info for "realtime"

Add some timers to the streamer code

Fixes #3264 with whitespace: no-wrap and flex-shrink: 0

On the standalone pages for replies, indicate the reply which the page
is for by lightening the usernames and bodies of other annotations in the
thread and darkening the username and body of the annotation whose ID
appears in the URL.

Disable a contradictory pep257 rule

Adds hashtag #annotated to web intent

Fix a type error where annotation objects rather than IDs were passed to
the streamer configuration on standalone annotation pages.

When displaying a standalone annotation page for replies, display the
entire conversation thread which that reply is in, including the
original annotation.

Previously standalone annotation pages for replies were broken because
only the reply itself was fetched, the the existence of the top-level
annotation was inferred from the reply's `references` field but because
it was missing, a blank "Message not available" card was shown instead.

Showing the entire thread fixes this problem and also allows the user to
see the complete context of the conversation.

Also refactor the tests to be less tied to the implementation details of
the class and expressed more in terms of what the view does from a
user's point of view.

Fixes #3367

Add a NIPSA service to replace h.nipsa.logic

Allow admins to toggle specific features for a features cohort

`selections()` tried to listen for a 'ready' event on the DOM Document
object. The 'ready' event however is jQuery-specific however so that
never gets triggered.

Instead change the `selections()` function to perform an initial check
for a selection on the next tick and emit a null|DOMRange.

Fixes #3452

Make the styling of quoted snippets of the page consistent with the
styling of block quotes in annotation bodies.

The styling for `<del>` and `<ins>` elements in quotes has been removed
because it is not currently used.

Fixes #3435

Load annotations from DB for /api/search

Set the annotation cursor to a pointer for annotation cards to indicate
that it is clickable (it scrolls the page to that annotation) except for
the body which has a text cursor to indicate that the text is
selectable.

Several places in the <annotation> component assumed that the `tags`
field was an array, as did <tag-editor>. The `tags` and `text` fields
are always set by the server for annotations received from the API but
are not set by Annotator when creating new annotations in the page.

It would be better to initialize all of the required fields for
annotations when they are loaded into the app rather than in the
<annotation> directive. For now however keep the initialization of all
required fields in the same place.

This fixes an error when saving new annotations.

Do not use query property in Feature.{all,remove_old_flags}

Do not use query property in Subscriptions.get_subscriptions_for_uri

Remove query property usage in h.groups

Extract tag editor into separate component and update ng-tags-input

This fixes some issues with Angular 1.5.x.
See https://github.com/mbenford/ngTagsInput/blob/master/CHANGELOG.md

Fixes #3324

As part of an effort to simplify the <annotation> directive and make
testing easier, split this out.

Pg cleanup

Add options page to extension, allow disabling badge

The idiomatic way to create derived data structures from data in the
Redux state store is to do:

  derivedData = transform(select(store.getState()))

Where the `select` function extracts the relevant fields from the state
and the `transform` function then computes the derived data. Both
`select` and `transform` can be trivially memoized to avoid unnecessary
recalculations.

This simplifies `root-thread` by avoiding inheritance from EventEmitter
and in future will make it easier to avoid rebuilding the thread if none
of the relevant application state has changed.

Do not use query property in User.get_by_username

Extract timestamp out into its own component

The util.createDirective() test helper assumes that directives have
controllers and reports an error if it fails to find one.

The simplest solution is just to add no-op controllers to the affected
directives.