GStreamer: Prepare GStreamer-1.4 switch.

Add old GStreamer-0.10 support code in new files
PsychXXXSupportGStreamer010.c, use the PsychXXXSupportGStreamer.c files
for the new GStreamer-1.4+ support code instead.

#define PSYCH_USE_LEGACY_GSTREAMER will enable compilation of the old
0.10 support files, lack of the #define will instead the new 1.4+
support files.

We will unconditionally use the GStreamer-1.4+ support in the future on
OSX and Windows, and for all Linux distributions (late 2014). It’s not
yet decided for older Linux distros if we will provide back ports of
1.4, or if we will continue to build 0.10.x versions for those old
distros.

-> New backup files for 0.10.
-> Conditional compile defines.
-> Xcode project gets the legacy files added for code browsing.
GStreamer-0.10: Replace deprecated functions.

Compile with GST_DISABLE_DEPRECATED showed use of two deprecated
functions. Replaced by good ones and verified stuff still works.

Make makefile be able to build old and new GStreamer backends.
GStreamer-1.4: Make playback engine functional.

Playback engine works, all tests i could do quickly seem to work.

- Playback forward/reverse/different speeds, start/stop.
- Seeking in both directions.
- Pixelformats 3,4,5,6,7,8 [1/2 don’t work with my movies].
- Multi-Threaded video decoding on supported codecs.
- Various different movies, also network streaming.
- Gapless playback variant 1 and 2.
- LoadMovieIntoTextures.
- Looped playback.
- Some bugs are automagically gone.

-> Screen for 64-Bit Octave on OSX rebuilt and tested.
-> Vidcapengine compile-time disabled, as it is tbd.
-> Step 1, we can have so much fun…
GStreamer-1.4: Make video capture and video recording mostly work.

As tested on OSX with internal iSight and external Logitech USB Webcam,
video capture and recording mostly works now.

-> Missing piece: video capture device enumeration via GstDeviceMonitor.
-> A-V Sync is horrible on OSX so far.
-> Other than that, works pretty well.
-> VideoRecordingDemo.m adapted to new caps format x-raw-rgb —> x-raw,
format=RGBA etc.
-> Pure recording now uses an appsink with 1 buffer capacity +
drop-frame instead of a fakesink.
-> All codec setup, caps etc. needed to be adjusted.
GStreamer-1.4: Make movie writing work - Part I

The obviously correct stuff. This beast doesn’t want to work at all so
far.
GStreamer-1.4: Make movie writing partially work.

Video writing works, Video+Sound doesn’t work yet.