Get "demo" related readline GUI stuff working with split jar.

* Move TextAreaReadline and IRBConsole to org.jruby.demo.readline.
* Modify jar-console target to repackage jline and readline jars.
* Update references for new package.
* Update jnlp examples for jar-console and new package.
* Update jirb_swing for new package.
* Add failover logic in readline.rb in case of single jar deploy.