Psychopy OSX 64-bit compatibility added

Got psychopy to work on 64-bit OSX systems, with pyglet 1.2 alpha 1
Corrected system check for pyglet.lib overload
Another corrected platform check

This one slipped my attention for a minute
Platform checks done right this time
Merge branch 'master' of git://github.com/psychopy/psychopy
RF: attributeSetter for Window.recordFrameIntervals
RF: attributeSetter for Window.blendMode
WIP - Untested VersionChooser Concept
RF/ENH: attributeSetters for Window methods.
DOC: updated doc for Window.color and Window.colorSpace
DOC: Window.gamma
ENH: a few new attributeSetters for Window.
DOC: added doc for checkTiming.
snake -> CamelCase
Just clone or checkout from ~/.psychopy/versions
Fetch new tags before checkout
Merge branch 'master' of git://github.com/psychopy/psychopy
Merge pull request #598 from lindeloev/master

attributeSettters for visual.Window
RF/ENH: attributeSetters for ElementArrayStim.
Only slightly controversial thing is removing the docstring from setColors() and referring to other stimuli. It's essentially duplicated.
RF: unified docstrings on color.
Merge branch 'master' of git://github.com/psychopy/psychopy
RF: changed demos/tests to use attributeSetters for ElementArrayStim.