OSX: Remove use of Gestalt(), adapt M-Files...

The iPhone company deprecated Gestalt() for future removal. Thanks,
idiots of Cupertino!
Rewrite Screen() and PsychTimeGlue to do without it: On OS X 10.9+ we
use some equivalent but more painful to use NSProcess Cocoa API for
Screen(), and some sysctl for code outside Screen mex where we can’t
easily access Cocoa api’s.

PsychGetOSXMinorVersion() works in all mex files, but only reports the
OS X minor version - the x in 10.x.y. It derives it from the Darwin
kernel major version, hoping that the mapping OS X minor = darwin major
- 4 stays stable in the future.

PsychCocoaGetOSXVersion() is only accessible from within Screen mex,
but provides the full major.minor.patchlevel string as Gestalt() did.
On OS X 10.10 that is, and presumably on 10.9, although there this
wasn’t public api. On 10.8 the new method will not work. From failure
we conclude we are on OS X 10.8 and simply return a hard-coded 10.8.5
version spec, as that was the last 10.8 version before the iPhone
company lost interest in maintaining their product. If you are on a
different 10.8 version - bad luck.

Adapt MacModelName and IsMinimumOSXVersion m-files to use the output of
Screen(‘Computer’) instead of Gestalt. Add a deprecation warning to
AppleVersion.m, which can’t be fixed and will simply die in some future
OS X version.

Suppress deprecation warnings for Gestalt mex, as there isn’t anything
we could do about it. It will simply die in some future PTB + OS X
Combo with no replacement.

-> Screen and Gestalt mex files for OS X rebuilt.