Linux Matlab makefiles: Make them work with Matlab R2012a

Need to escape our *.c and *.cc globs with "", so mex compiler
of R2012a+ doesn't bail.

-> linuxmakeit_ubuntugutsy.m and linuxmakeit64_ubuntugutsy.m
   for 32/64-Bit Matlab on Linux modified.
New function PsychDefaultSetup()

PsychDefaultSetup is supposed to reduce boilerplate code at the
top of typical scripts. It performs a couple of frequently needed
setup steps. A mandatory 'featureLevel' parameter tells how to
setup and also how to choose defaults:

Level 0: Only execute AssertOpenGL
Level 1: Additionally execute KbName('UnifyKeyNames').
Level 2: PsychImaging('AddTask','General','NormalizedColorRange', 1)

The latter one, if windows are opened with PsychImaging('OpenWindow')
will switch the window to an unclamped colorrange of [0;1], and apply
that color input range also to standard 8 bpc integer textures if the
imageMatrix is passed to Screen('MakeTexture', window, imageMatrix, ...)
as a double class matrix. This allows use of a unified normalized 0-1
range for clearer code and independence of output display device
color resolution.

-> New function PsychDefaultSetup.m
-> PsychImaging.m extended to honor Level 2 setting of PsychDefaultSetup.m
Screen: Make Screen('ColorRange') less verbose for unclamped color range.

As unclamping the color range is now default behaviour if
PsychDefaultSetup(2) is used, we don't want all the info
about color clamping precision and how to test it anymore.
Way too much clutter.

-> Screen mex files for 64-Bit Octave and 64-Bit Matlab on Linux rebuilt
   and tested.

-> This is build against R2012a, so needs a recompile against our standard
   R2007a for consistency before release.
PsychDebugWindowConfiguration: Disable high precision timestamping on all OS'es.

Not only on OSX, but also on Windows and Linux. This is needed to
avoid timestamp warning clutter on modern setups if transparent
onscreen windows are on.

Also clean up help text a bit.