Added a JRuby 1.7.11 recipe.
Merge pull request #515 from nirvdrum/jruby-1.7.11

Added a JRuby 1.7.11 recipe.
Add support for JRuby 9000 bundled with the Graal VM

JRuby 9000 (the next major release) includes a backend that supports a
new JVM JIT compiler called Graal. Graal is based on OpenJDK but hasn't
been released yet.

http://openjdk.java.net/projects/graal/
Add test for JRuby+Graal
Merge branch 'graal'

Closes #514
ruby-build 20140225
Fix typo in CHANGELOG [ci skip]
Fixes check for user-specified definition

Better to use -f than -e to check for a user-specified definition file.
With -e, if the user accidentally types the name of a directory (or, far
less likely, a device file) with the same name as the Ruby they're
trying to install, they end up with ruby-build doing absolutely nothing
at best, or an error message that could be pretty confusing at worst.
Merge pull request #518 from dpoggi/better-user-specified-definition-check

Fixes #517
Merge branch 'sstephenson-master'