Tidying.

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

Change-Id: Idadc982cc8f37aec4404ec8ec26d0a5b1f0515ad
Reviewed-on: http://gerrit.dmdirc.com/3842
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>