Big Gstreamer update:

Update gstreamer, gstreamer-plugins, -good, -bad and -ugly ports to 1.4.4.
Update gstreamer1-plugins-gnonlin to 1.4.0.
Update py-gstreamer1 and py3-gstreamer1 to 1.4.0.

Add multimedia/gstreamer1-editing-services. GES is a high-level library
for facilitating the creation of audio/video non-linear editors.

Add pulseaudio plugin now that pulseaudio is updated and add the gl plugin.

Drop :keepla from USES=libtool.
Drop @dirrm[try] from plists and drop gnomehier from USE_GNOME
Switch to optionhelpers in multimedia/gstreamer1.

PR: 194922 (merged with my own WIP)
Submitted by: olivierd