Rename TeensyKey sketch: conflicts with OSX build.

I tried building this on a Mac today (10.9) and the TeensyKey directory
conflicted with the executable name since OSX picky about case.
Remove -arch ppc

I tried building this on OSX Mavericks (10.9) today and -arch ppc just
got in the way. I'm not a C developer so I just tossed it and hoped. It
worked. (I did have to change the SDK path though.)