fixed SHOWWINDOW
SDL port

As far as I can tell no functionality has been lost, but I'm not really
sure what an "expose" event in X11 is. I think that just handled
minimization which SDL _should_ do for us automatically.
Preliminary getopt parsing.

This moves the code more firmly into posix-land, but there are a bunch
of other posix calls still in the code anyways. Sorry, windows users.
more getopts
opts for verticies and polygon count