Re-enable warnings on plugins building

Change-Id: Ia4b0279b0db183c9267c39e9ecc2387d21f5fa11
Reviewed-on: http://gerrit.dmdirc.com/3094
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
Remove deprecated method.

Change-Id: I81c0f466fc01929d60b6d52a2fdf1c02ef64a063
Reviewed-on: http://gerrit.dmdirc.com/3095
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager