As suggested in:

    https://github.com/hypothesis/h/pull/1868/files#r23171034

Annotator#isAnnotator provides better answers as of
openannotation/annotator@368b5cf.

This commit is intended as a pure refactoring. No behaviour should be
changed.

There is no need for a variable name if it is just returned immediately.

Allow simple usernames

Simplify the front-end code that transforms annotation permissions
objects into ACLs. Since the front-end does not have to be exposed
to the system principals and special "all" grant used by Pyramid it
only needs to have special handling of the "group:__world__"
principal; others are unused.

Allow the persona filter to pass invalid account URIs through unharmed.

Replace Annotator with dist build

Replaces the inlined CoffeeScript with a vanilla v1.2.x Annotator from
upstream!

Move on to vanilla annotator + a herd of monkeys.

1796 add any field handling for search api

Resolve user authorization before view render.

This commit moves most customisations of the upstream Annotator v1.2.x
into annotator_monkey.coffee, which monkeypatches the Annotator object.
Customisations required by the anchoring subsystem are moved into the
"enhanced anchoring" plugin.

With this change, we should be able to replace our inlined Annotator
source with the built JavaScript for upstream Annotator!

This file provides an abstract base class that's only used in one place,
so this commit just moves it into the one place where it's used.

Avoid having to watch the user in route controllers at all by resolving
it as a prerequisite of the routes, much like the store bootstrap. The
user may still be ``null`` but it will not be ``undefined``.

For clarity, the $routeChangeStart handler is changed back to a
function, ``cleanupAnnotations``, that is called explicitly from
the user watcher in the ``AppController`` right before the route
reloads.

Set the FF addon version at build time

Towards vanilla annotator

Most of these changes are either syntactic or should not change
behaviour.

This contains only syntactic changes, but it makes it easier to see an
ever-diminishing diff with upstream Annotator.

We monkeypatch BrowserRange as needed in range_monkey.coffee

This is not in upstream and it's not needed any more.

Remove Annotator.Notification.

Move juicy anchoring bits into a plugin of Annotator

Threading events fix and tests

Rather than looping through all threads, use the references property
to find the parent directly. It should be guaranteed to exist since
one cannot reply to something which does not have an id.

Furthermore, when there is no parent reference, the root serves as
the parent. Without considering this, deleting top level annotations
leave stubs in the UI.

Add some tests that the events do what they're supposed to. NB: the
thread method itself should probably be tested.