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
fixup a mistake and a potential problem identified by Mario
Merge pull request #205 from dcnieho/showCursorSimplify

Show cursor simplify