Inject more things into the DCC manager.

Also deprecate the getters in the SwingController that should be
avoided in favour of injection.

Change-Id: I0a6ccc960a4e08d0a7c6afc08a75b89d2b17c125
Reviewed-on: http://gerrit.dmdirc.com/3035
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>