Merge pull request #684 from deepj/master

Add definition of Ruby 2.2.0-rc1
ruby-build 20141222
add jruby-1.7.18
Merge pull request #687 from neojin/add-jruby-1.7.18

add jruby-1.7.18
added definition of ruby 2.2.0
Merge pull request #688 from hsbt/ruby220

Added definition of Ruby 2.2.0
ruby-build 20141225

Closes https://github.com/sstephenson/ruby-build/issues/689.
Update examples to use 2.2.0
Add Ruby 2.3.0 dev definitions