Tidying.

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

Change-Id: I80c52ef8c39d9fc45038921285dd85bba6b397d4
Reviewed-on: http://gerrit.dmdirc.com/3843
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>