MRI Versions Available Updated

Updated the overall list of MRI versions available in the list. Will
handle IronRuby and JRuby changes separately. Will also have to consider
DevKit changes to account for Ruby 2.0 changes.
DevKit Additions for Ruby 2.0

Updated the list for the Ruby 2.0 versions of DevKit (32-bit and
64-bit). List looks a bit funky so may change the listings at a later
time.