Cleanup font icons and add Markdown glyphs

We now only have one of each icon type where possible.

Sync the bridge after beforeAnnotationCreated

Spotted by @gergely-ujvari

This ensures that plugins on both sides have fired and any resulting
modifications are synchronized (document plugin, for instance).

Fix #1502

Remove parent and url values in streamer and notifications

Conflicts:
	h/static/styles/app.scss

Change save shortcut to meta/ctrl + enter.

Classes had been added to the stylesheet but not to the template, and
those that were had typos.

This was causing the annotation to render with too much whitespace now
that it uses sections rather than divs.

Hyphenate camel case filenames

Add sphinx to doc

Overhaul view and sort behaviour.

Sending the "more_hits" message when no past data filter has been
configured results in an exception in the backend and disconnection
of the socket.

Re-introduce the flash messages when attempting to reply to and
share unsaved annotations. Doing so is better than hiding them
because hiding them results in newly created annotations changing
layout when the id is returned from the server.

The view data is up-to-date with whatever the user entered already
and a re-render will happen again when the permanent id and timestamps
return from the server anyway.

I acted too quickly on these edits. I can squash them up.

Reduce the template logic and remove a use of 'group:__world__'.

This is semantically clearer than checking whether the tool is
highlight.

The threadFilter only needs to be tracking the single message in
the container. It is the deepCount that aggregates the results.
There's no longer any reason to cache a __filterResult.