This commit fixes problems with FSAA (full-screen video card antialiasing) with selection.
It turns off FSAA for the backbuffered select drawing function.
Since opengl's extension system is incomphrehensible to me (at least not without committing glew), I've
basically done a little hack that detects if the value we need for glDisable (MULTISAMPLE_ARB) is defined,
and if not defines it. Also, this commit only works on windows, because glx sadly seems to not support
arb_multisample at all, and in all likelihood neither does osx.
Joe
61c8471ebd