SERVER-1268 - std-aliasing symbols like 'string' in global namespace collide with MongoDB headers.

I did a complete patch earlier which allowed the client library and tests to be built despite std:: symbol aliases in the global namespace in user code but, because the patch changed so many symbols I feared it would get out-of-date fast. So this is more of, the tools to fix SERVER-1268 with when someone is ready to. The first patch is a test, a mock-client file with the global namespace thoroughly polluted. It's part of 'client' target. The 2nd is a script that does the bulk of the work of fully-qualifying std symbols in a given header file (some things must be done manually still - see the top of the script itself (1268.pl) for details).