Screen/OSX: Compile fix for dc1394 video capture engine.

Add missing variable in OSX specific capture timestamp remapping.
osxmakeitoctave: Adapt to Octave's expected version roadmap.

Octave 3.6.4 was the last release of the Octave 3.6 series.
It will be followed by Octave 3.8.0 very soon, and possibly a 3.8.1 or
- much less likely - a 3.8.2. Therefore cut off our support at 3.6.4
and add 3.8.0 - 3.8.2 as successors.
We also add (optimistically) support for the next-gen 4.0 series with
4.0.0 and 4.0.1, in the unlikely case that the naming schemes and path
structures will stay exactly the same in the future. Who even knows if
our 3.8.x path scheme will be valid?
Documentation updates related to video capture/recording.

Also whitespace fixes, and move VideoDelayLoopMiniDemo into the
PsychDemos folder.
GStreamer.m: Update help text, reenable Homebrew GStreamer.

Update help text.
Stress even more that user needs to install all packages of the
GStreamer-SDK.
Reenable updated install instructions for GStreamer-0.10 from OSX
HomeBrew.