Add support for DataDrivenDBInputFormat & Add a JDBCScheme builder. 

This is a rough port from Hadoop with the minimal amounts of changes needed. I also added a builder to JDBCScheme to help with the various forms of constructors. This can definitely be done more cleanly when moved to https://github.com/Cascading/cascading-jdbc.

See user group discussion: https://groups.google.com/forum/#!topic/cascading-user/HbJdrLKOLH8