Build Ruby 2 CentOS appliance

This is now ready for review and merge.

TODO:

- [x] Get ruby-install built
- [x] Install ruby 2.0.0
- [x] Verify bundling works (ruby environment is properly loaded)
- [x] See if we can build qpid_messaging or punt into a followup PR [#953]
- [x] Verify building of shared objects works
- [x] Variablize the ruby version (ruby 2.0.0-p576) - can't do until ruby-install honors --update to update it's own list of rubies
- [x] Remove references to my fork/repo/branches

See #837
Yes, I can change the comment.  I don't think it makes sense to bury dependencies in ruby-install when those dependences are really ruby dependencies.  I'm debating disabling ruby-install auto-installing dependencies mainly because it hides the appliance's dependencies in an external library.