Psychtoolbox 3.0.11 final

* Workaround Mesa OpenGL bug on Linux.
* Refine nouveau-kms bug workaround for Linux 3.13+
* Make GStreamer backends compatible with Octave 3.8 GUI on Linux.
* Refine Screen('Computer') on Linux/Windows.
* Some cleanups.
* Most mex files rebuilt for 3.0.11.