Bundle GLEW

Bundles GLEW 1.10.0, released 2013-07-22. This should help avoid problems when building on systems that don't have a recent version of GLEW installed.

I think I've got rid of all references to system GLEW from the autotools build, except for the debian control file (which I'm not sure what to do about since debian has rules against bundled libraries). The OS X and MSVC builds have not been updated (and will be broken by this change until they are updated, I'm sure).