PTB BETA RELEASE "Blue skies and empty brains" - SP2

Mostly bug fixes and minor improvements, most interesting is probably the Eyelink() stuff.

* Fix download failure for legacy v3.0.10 in DownloadPsychtoolbox() on 32-Bit Matlab for OSX.

* Fix mex file load errors on 64-Bit Octave for OSX with Octave installed via Fink package manager and for other versions of Octave than 3.6.1 with HomeBrew.

* New function Eyelink('SetAddress') for setting tracker computer target IP address, to allow selection of non-default IP address.

* Enable raw sample data access for Eyelink on Linux. This requires the latest Eyelink packages for Linux, Windows, OSX. For entertainment value, SR-Research provides up to date 32-Bit packages for Debian/Ubuntu Linux via automatic software update, but delivers outdated and incompatible 64-Bit packages via software update, despite matching version numbers and release dates! However, downloading and manually installing the .tar archive for 64-Bit from their Linux support area works fine. Great release engineering guys, i had so much fun with this!

* Updated help for PsychVideoSwitcher by Xiangrui Li to clarify how the toggle between Luminance and RGB mode works.

* Update some other help texts, e.g., DisplayOutputMappings, to describe multi GPU support/issues/workarounds.

* Add new text rendering mode 0 on OSX for new-style ATSU rendering of problematic exotic fonts. Screen('Preference','TextRenderer', mode) still defaults to 1 on OSX, but a setting of 0 uses a different layout strategy which handles some fonts better, e.g., Denis Pelli's "Kuenstler LT", while breaking layout for other fonts, e.g., Japanese Kanji. Great work Apple, you rule! The best solution is actually to use mode 2, which uses the (ported) Linux text renderer instead of the Apple text renderer on OSX. That renderer handles all known fonts at same or better quality and flexibility with much higher performance. However, we stick to classic mode 1 on OSX for reason of consistency, so modes 0 and 2 are opt-in.

* Add GstX264Enc video encoding profile for fast camerabin2 video recording with GStreamer SDK. This makes VideoRecording work reasonably well with the GStreamer-SDK on 64-Bit Windows.

* Some new demos and improvements from David Brainard in area of color calibration or simulation, e.g., IsomerizationInDishDemo.

* New function GetGITPath from Ben Heasley.

Enjoy,
-mario