jruby-gradle-jar-plugin is walking upright

In this changeset:
+ Jar task type extended with `jruby` closure
+ Ability to add custome gem directories
+ Ability to make a JAR executable using `warbler-bootstrap`
+ Ability to make A JAR executable supplying own main class
The war plugin relies on a jrubyWar configuration. I'm not objecting to this but I dont grok the ue of test and runtime gem configurations for rubygems since they dont quite match the pattern that other gradle dependencies do