(PUP-2521) Remove Ruby 2.0.0 windows-pr gem +deps

 - With our gemset being FFI based, we no longer need to rely on
   windows-pr gem.  That also removes the need for the windows-apii and
   win32-api gems.
Merge pull request #42 from Iristyle/ticket/2.0.0-x64/PUP-2521-remove-windows-pr-gem

(PUP-2521) Remove Ruby 2.0.0 windows-pr gem +deps