ShowCursor: simplified and added check
- when get to Screen call, type is always numeric or empty as parsed above, so simplified screen call code
- added extra check in persing though to make sure type is numeric
- case error in oldtype returned at bottom of function, removed redundant one at the top
Merge pull request #204 from kleinerm/master

Pull current state into public master.

* Linux final nouveau-kms and msc fixes.
* AMD MULLINS support for Linux and PTBKD.
* Prototype implementation for stereo crosstalk reduction - just the support infrastructure.
* PsychtoolboxVersion supports NeuroDebian.
* Smallish cleanups.
fixup a mistake and a potential problem identified by Mario
Merge pull request #205 from dcnieho/showCursorSimplify

Show cursor simplify
Merge pull request #46 from Psychtoolbox-3/master

Resync with current master of official Psychtoolbox-3 repo.

ShowCursor changes of Diederick.