CPU Information

This change adds in some functions for retrieving top level CPU information.
I'd like to try and keep it all in once place instead of calling part of pycpuid from one place and part of it from other.  It keep the documentation in one place and isolates us from any API changes to pycpuid in the future.  Also since this is relatively new it will be easy to post-process output in a single location if we find out the results are inconsistent or incomplete.