- Pass in ID
- Don't burst the full backbuffer

Spark doesn't work with recent versions, old versions of Jetty
have nasty bugs, and spark doesn't really give us much benefit.

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.

Migrate all users to using the InputModel.

These will be going away shortly.

This adds an 'initial state producer' to create the burst of
state clients will receive on connect, and serialisers for
WindowModels and BackBuffers.

The handler can't be dependency injected (as it's created by the
framework) so, in order to minimise the amount of static
horribleness, pass in a controller which can do the actual work
and have proper dependencies.

Now with working dependencies and webserver.