Implement "Always-On Annotation" and "Highlighting" modes
Annotation loading cleanup #1

Manually cherry-pick some changes from

https://github.com/hypothesis/h/commit/c2286994a215283addd86170851e4cabf3e97ca9
https://github.com/hypothesis/h/commit/1ff5505f3b019e2abd21b6920a388d798c0acc58
https://github.com/hypothesis/h/commit/fa9351f02c996cebf8a10f1ef8bb8bbaa1035286

This partially takes care of
 * Problem 1 described in #578. (The two code path are not yet consolidated, but at least now they do the same)
 * Problem 3 (The reloading is now a separate method.)
Added framework for Social View support, with single player demo

Now the Hypothes.is class has a field called 'socialView',
which specifies the social view filters that should be used.

This is considered when loading annotations on init, and also on
later re-loads, because of login/logout.

When the filter is changed, annotations are automatically reloaded.

(And there were also some cosmetic fixes.)
Added SocialView hook for Highlighter Mode
Fix merge bug
Fix bug when searching for the first time in a browser
Do not load the annotations from the original href twice
Streamer backend bugfixes:
- Reversed operator order for the python contains() operator (b in a)
- Added try-catch block for after_action()
- More PEP8 style
Initial solution
- Graphical design is missing
- Fix for refreshing synonims is missing
Adding .
Introducing bottombar for notifications
Formatting notification card
Notifications for the speech bubble
- Flashes for new notifications.
- Notification number is counted in the bubble.
Counting changes instead of notifications for sidebar icon
Polishing notifications:
- Added font family
- Bottombar has it's height decreased
- Centering the changes for the center of the speech bubble icon
Fix rebase for streamer.py
Added missing </script> tag
Notification throws out not relevant annotations when the social view mode is set to 'single-player'
Merge pull request #616 from hypothesis/highlightning-with-social-with-notifications-1

Feature cocktail for current Demo