Fix tests that don't work in parallel.

Make the ColourManager into a proper class so it can have
dependencies, just like a real boy.

Change-Id: Ib49f046f7dee6f240cb0970603b4fcd3d71f3cba
Reviewed-on: http://gerrit.dmdirc.com/2696
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
Move more initialisation into dagger.

Fully initialise the PluginManager instead of passing around
one in various states of existance.

Move plugin extraction logic into a CorePluginExtractor class.

Inject UpdateManager where appropriate.

Change-Id: I6c15f7682cccd93b40dcc189a0a8466d067095f0
Reviewed-on: http://gerrit.dmdirc.com/2692
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager