- GroupChatManager never subscribed to the event bus
- Comparing Optional<Connection> to Connection fails

Closes #782

Stop swimming against the tide and accept what most of the rest of
the world does.

While it adds an annoying depth to the actual source code, it makes
the root directory nicer (no more 'test-res' dirs), means we don't
have to override the gradle config, and makes it nicer to work in
IDEA 2016.1.

In preparation for child eventbusses being removed, anything
trying to subscribe to specific windows now needs an explicit
check.

Issue #662

Migrate all users to using the InputModel.

This will go in a plugin instead.

Delete the duplicated methods from Connection.

Nicer than having Channel poke it explicitly.

For now this is just a straight(ish) copy of the way Server worked.
Need to make it use events in the future which should simplify it
quite a bit.