Add netbeans license header

Change-Id: Ifbcd6ed48676f85cb642fbff1254ecb6c8fee498
Reviewed-on: http://gerrit.dmdirc.com/3033
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
Update submodules: plugins (new commits)

plugins:
    e55347f Chris Smith <chris@dmdirc.com>
            Remove some SwingControllers from DCC plugin

            Gerrit: http://gerrit.dmdirc.com/3034

Change-Id: Ib99ba4fc111c66cd68f99115bfcf80f73aa2b269