This keeps bootstrapping functions in one place and makes it much easier
to disable such calls in the test environment. The check currently
uses the mocha global variable, in future it would be nicer to have
an APP_ENV flag or similar defined before the tests run.

This causes really hard to track down errors when $digest is called. In
reality though this still needs a more robust fix.

The idea is to keep bridge and discovery code agnostic of the
application.

This makes it easier to provide consistent interface between the
annotator event system and the angular one.

Not too pretty..

Now we refer to the object sent over the wire as the message body,
an annotation is then extracted from this object.

[ci-skip]