Final a few things

Change-Id: I22300a4ec7a09ee30a1fbc4d6fb91ff049ca3e39
Reviewed-on: http://gerrit.dmdirc.com/3839
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
Tidying.

Remove pointless super() calls.
Remove redundant interface decs.
Remove unnecessary enum annotations.
Change .length == 0 to .isEmpty.

Change-Id: Ic89c70772063157e970f046b1cd04980a60bc1a8
Reviewed-on: http://gerrit.dmdirc.com/3844
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager