PsychKinectCore: Fix wrong matrix dimensions of 'GetImage'

PsychKinectCore('GetImage') returned a matrix with flipped height and
width dimensions, requiring awkward reshape() operations to make any
use of the returned matrix. Now fixed. Also added a description to the
online help text on how to convert the returned image matrix into
something Matlab/Octave's image processing toolbox / imshow() /
imwrite() et al. understand. Some help texts improved.
Clarified that the driver currently only suppports XBOX-360 Kinect, but
not yet the "Kinect for Windows".

PsychKinectCore for 32/64-Bit Matlab on Windows and 64-Bit
Octave/Matlab on OSX rebuilt. Rebuild for Linux pending. We won't
rebuild or fix the driver for 32-Bit Matlab on OSX anymore, as 32-Bit
PTB for OSX is deprecated and this is the kind of exotic and work
intense maintenance stuff we won't do anymore for a dying platform.

Also cleanup to the demos.
Screen/Windows: Rebuilt + Compiler (warning) fixes.

Rebuilt for testing. Fixed a compile error in new Gstreamer vidcap
code. Fixed various compiler warnings, so that it now compiles almost
cleanly, except for some deprecation warnings wrt. to GStreamer which
we have to live with for the time being on all platforms.

Screen for 32/64-Bit Matlab on Windows rebuilt.
Screen: Properly reset flip and missed deadline counters.

So we don't get weird results like 3 out of 1 flips missed ;-).
Screen: Implement PsychCleanupDisplayGlue() on all platforms.

This function, formerly Linux only, now also exists on OSX and Windows.
It is called during Screen shutdown to release the display glue - the
stuff that happens in PsychScreenGlue. The routine shall cleanup
whatever display and graphics related resources are held while the
Screen() file is loaded.

On Linux it releases XInput and X11 display connections -- basically
disconnects from the X-Server.

On OSX it disconnects from the PsychtoolboxKernelDriver and releases
CGDisplayReconfigurationCallbacks. This was formerly done in a hacky
way.

On Windows it releases display system resources.

-> Much cleaner solution, no more hacks here.
Screen/Windows: Implement PsychCleanupDisplayGlue()

The function now properly releases GDI device contexts for the
different displays (monitors) connected. It also releases the
DirectDraw7 interfaces which we use for beamposition queries and
unloads the DirectDraw DLL itself.

This should avoid/minimize resource leaks at Screen exit time on
Windows (see ptb forum message #13471 for potential symptoms).

Also fix some failure to release window device contexts in some
error-out path of 'OpenWindow'.

Closes issue #39

Screen for 64-Bit Matlab on Windows rebuilt and tested.
Screen/GStreamer: Add setup of multi-threaded video decoding method.

If multi-threaded video playback is requested, check if the
"thread-types" property is supported on the selected video codec. If
so, set it so that the codec uses both slice-threading and
frame-threading for parallel decoding.

By default, the GStreamer-SDK's codecs and current upstream master only
use slice-threading for decode, because frame-threading can cause
visual artifacts with some movie formats and has higher latency, which
can be bad for video teleconferencing applications and such. However,
we only do latency insensitive playback of formats we know that work
with frame-decoding (opt-in of users), and frame-decoding has much
higher performance/scalability. Therefore we absolutely want
frame-threading in addition to slice-threading and need to set the
property to a proper non-default value, as the default would be
slice-threading only.

The property itself is not yet implemented in GStreamer at time of this
commit. This is tbd by me soon in upstream GStreamer.

See
http://cgit.freedesktop.org/gstreamer/gst-ffmpeg/tree/ext/ffmpeg/gstffmp
egviddec.c?h=0.10#n519 for a reference to the code that needs to be
changed in the gst-ffmpeg plugins. See
https://bugs.freedesktop.org/show_bug.cgi?id=56206 for the discussion
on this gstreamer feature request.

Screen for 64-Bit Matlab on Windows rebuilt.