Use @PluginDomain in a few places.

Change-Id: Iac7e1032d07efacf95d8179b09fd352ba0d6c558
Reviewed-on: http://gerrit.dmdirc.com/3186
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
Use @PluginDomain everywhere else.

Change-Id: I638186bb258a83ff21c79e2425eac25688a6c6ed
Reviewed-on: http://gerrit.dmdirc.com/3187
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager