[WIP] Build Ruby 2 CentOS appliance

VERY EARLY... DON'T MERGE.

Kicked off a build that I need to test again on Monday.

TODO:

- [x] Get ruby-install built
- [ ] Install ruby 2.0.0
- [ ] Verify bundling works (ruby environment is properly loaded)
- [ ] See if we can build qpid_messaging or punt into a followup PR
- [ ] Verify building of shared objects works
- [ ] Remove references to my fork/repo/branches

See #837
If there's only one ruby and you want to keep this flexible, you can probably do `export PATH=$PATH:/opt/rubies/*/bin/` or something to that effect.