This is just an IntelliJ refactor, using EventBus in place of
DMDircMBassador whenever possible.

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.

Instead of wrapping the source event and modifying it, they are
now proper events that are displayed themselves (and the original
message is suppressed).

This allows highlights to be formatted differently.

Issue #669

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

Issue #662

This is horribly icky and wrong. The only place it's used is
PluginFilesHelper, which can easily be given its own manager.

Also fix annoying shaded import.

Alternative highlights were never added because the maps were
optimised away; then the list occasionally ended up with null
entries as they were added concurrently.