ruby-build 20121227
Delegate to `rbenv-help` for usage, if available
Fix `rbenv-help` invocation
Add summary lines for `rbenv install` and `rbenv uninstall`
Point people to the readme
Added a recipe for JRuby 1.7.2.
Merge pull request #262 from nirvdrum/add_jruby_1.7.2

Added a recipe for JRuby 1.7.2.
ruby-build 20130104
Definition for ruby 2.0.0-rc1
Merge pull request #265 from mariochavez/master

Add definition for Ruby 2.0.0 rc1
Debug versions