Screen/PsychImaging: Add support for ~11 bpc framebuffers.

Add final setup code to Screen and PsychImaging for requesting
11 bpc framebuffers, and to provide 11 bpc framebuffers on AMD
cards under Linux and OSX, if the OS doesn't support these
natively.

Cleanup the 10/11 bpc framebuffer handling code and hopefully
make status messages for user more streamlined.

Cleanup/Update the PsychImaging help texts with what we
learned so far in our HDMI deep color adventures.

Add 11 bpc option to our two standard high bit depth demos
AdditiveBlending... and BitsPlusCSFDemo.

-> Actual mex files will go to separate commits, to keep this
   mergeable to the 3.0.11 release if we should decide to do this.

-> New code not yet tested on actual hardware.
Screen/Linux: Use old-style override-redirect even on KDE by default.

New-Style method for KDE doesn't play well with KDE multi-head setups,
and causes windows to be cut off, so only parts of the window show up
on dual-display presentation.

May need to rework this thoroughly but for now just disable it.
KDE's KWin works nicely with our fullscreen windows if the user
simply tells KWin once to unredirect fullscreen windows:

Go to: KDE System Settings -> Desktop Effects -> "Advanced" Tab ->
"Suspend desktop effects for fullscreen windows"
-> Check the checkbox, "Apply" -> Done.

Override redirect new-style can be forced on by
setenv("PSYCH_NEW_OVERRIDEREDIRECT", "1")
for experimentation.

-> Successfully tested to do the right thing(tm) on Ubuntu 14.04-LTS.
Screen/Linux: Restrict nouveau-kms pageflip workaround to Linux 3.13-3.15

The relevant bugs are fixed in Linux 3.16+, so are only present
in 3.13 - 3.15. Backports to 3.13-3.15 will likely happen, but
haven't happened yet, so leave workaround for those kernels active.
Rebuild Screen for 64-Bit Octave on Linux for testing.