rewrite of code base and added support for IronCache and IronWorker

Added IronCache.class.php and IronWorker.class.php to Iron.io directory.
Complete rewrite of iron_io library to add functionality of new classes.
Modified config file iron_io.php to support new classes and different
hostnames.
Update README.md
Update Iron_io.php
Update README.md
Update README.md
Merge branch 'master' of https://github.com/jrutheiser/Codeigniter-Iron.io
fixed config
Merge branch 'master' of https://github.com/jrutheiser/Codeigniter-Iron.io