DOC: fix for val2array.
ENH: _setWithOperation now handles power and modulus.
And made it a bit nicer to read.
DOC: couldn't spell deprecated. Now I can.
RF+ENH: made visual.Window.getActualFrameRate() public and added an option to control precision.
Merge remote branch 'jonas/master'

Conflicts:
  psychopy/visual.py:
    - jonas had moved getattr(self, attrib) to store a temp attribute `oldval` but not faster (slower?)