sys/glsink/: Add gltestsrc element, a duplicate of videotestsrc that uses

Original commit message from CVS:
* sys/glsink/Makefile.am:
* sys/glsink/gltestsrc.c:
* sys/glsink/gltestsrc.h:
* sys/glsink/gstgldisplay.c:
* sys/glsink/gstgldownload.c:
* sys/glsink/gstglfilter.c:
* sys/glsink/gstgltestsrc.c:
* sys/glsink/gstgltestsrc.h:
* sys/glsink/gstglupload.c:
* sys/glsink/gstopengl.c:
Add gltestsrc element, a duplicate of videotestsrc that uses
GL rendering to create images.  More cleanup.
10 files changed