wmllint: activate wildcard globbing on Windows

The Windows cmd shell does not expand wildcards by default, unlike UNIX shells. This imports glob.glob and runs arguments through it on Windows. If the wildcard pattern does not match anything, warn and sys.exit(2).

Frontported (in modified form) from my 1.4 work!
Windows sys.argv again: sys.exit(2) when too complicated, and deliver an explanation in stderr

I noted last time that my "fix" could not cover all possibilities. After further thought, I decided that the best thing to do in the hard cases is to sys.exit, and give users a clear explanation in stderr so they can re-enter their paths correctly.

If users think they need more help, I offer them a chance to get a more detailed explanation through raw_input. Given that many users nowadays are unfamiliar with the command line (even moreso on Windows), I wanted to give them plenty of hand-holding.