#65 compiler warning fixes

[Nido Media]

This patch fixes a few compiler warnings by either removing unused variables, changing format arguments, or casting int's to unsigned integers of the right size.
Also removed an unused 'mymin' function (though I think its copy in another file and 'mymax' should probably be replaced by std::min and std::max).

[Vincent Legoll]

hello,

Just FYI, I started a while ago a quilt series for fixing various compile warnings (with both llvm/clang && gcc-4.7). it's now posted in https://sourceforge.net/p/vegastrike/patches/66/

I think there is some overlap with your patch, though...
We should try to avoid duplicated work.
I'll update my series if your work goes in.

If you want a combined patch, or the quilt series as a tarball, just ask.

Thanks