Screen/OSX: Rewrite screen glue to remove/fix use of deprecated functions.

Rewrite screen glue to use functions which are supported/current as of
OSX 10.9, to replace functions which are deprecated since 10.6.
Add missing function prototype of CGDisplayBeamPosition() - which was
completely removed in the OSX 10.9 SDK - until we decide if we should
already kill it completely, or let it linger around for a while longer.
Current status:
10.6 - Only works on NVidia gpus, 10.7 - Ditto, but slightly
broken/inaccurate - PTB driver is better solution, 10.8 Severely broken
for everything bug VGA-CRT's, 10.9 completely dysfunctional (always
returns zero on NVidia card).
Remove unused PsychGetNumScreenPlanes() function for all os'es as a
cleanup.

-> Screen for 64-Bit Matlab on OSX rebuilt and lightly tested.
Screen/GStreamer: Silence deprecation warnings on at least OSX and Linux.

When building on GLib version 2.32 and later, disable warnings about
deprecated API calls. This to silence g_value_array_get_nth() and
g_value_array_free() deprecation warning on GLib 2.32+. We know that
GValueArrays are deprecated and should be replaced by GArray's, but
some GStreamer-0.10 functions still use them, so we have to use them as
well until we upgrade to GStreamer-1.0 at some point.

Makes compiler output less cluttered. Also remove some deprecation
warning suppress from OSX Window glue when we're at it - it is no
longer needed.