packagegroup-gnome: include missing gsettings files

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
packagegroup-gnome-apps: include cheese and abiword

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
gstreamer: ALLOW_EMPTY_-apps = 1

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>