HIDIntervalTest: Make robust against uncooperative users.

Closes issue #135
DeinterlacerTest: Fix regressions due to changes in Screen().

This is ancient in its way it sets up shader parameters and should
probably get converted to our procedural shading api, but i'm not in
the mood for this now. At least make it work the ancient way.

Fixes issue #136
MinExpStair / MinExpStairDemo: Don't work on Octave.

They use nested functions which are not supported on Octave. Abort more
softly.

Fixes issue #138
FitConeFundamentalsTest: Does not work on octave.

Due to use of nested functions which are not supported on octave, and
due to use of fmincon  function which isn't supported either and even
optional on Matlab as part of the Optimization toolbox.

Abort softly on Octave.

Fixes issue #137
MovieDemo: Beautify code.
Rush(): Clean up help text, remove lots of outdated info.
Priority(): Improve help text, remove OSX 10.4 support.

Remove handling if OSX Unix updated process, ie. starting and stopping
the updated daemon. This was needed on OSX 10.4.7 and earlier, no
longer needed on later OSX versions. As we don't support 10.4 anymore,
this is now moot.

Delete all functions related to handling of the Unix updated process.
FitWeibullTAFCTest et al.: Don't work on octave.

Add some comments to note the lack of octave compatibility:

The implementation of the optimization toolbox function fminunc() on
octave is less capable. It only accepts the first 3 parameters of its
Matlab pendant, not additional optional parameters.
Psychtoolbox top-level help file: Update it to current state.
Delete orphaned docu file HookProcessingChains.m

Fixes #142 about incomplete docu file by deleting the incomplete docu
file.
Finally something easy and straightforward to fix.