Initial impl

This InputFormat allows decoupling the format of the data from the actual jobs. It implement isolation from classloader and configuration perspective.
It is intended as a better MultiInputFormat which allows reading a single input from multiple locations with different inputformats coming from separate isolated class loaders (child first class loading delegation) and configurations.

I would consider using the trick I did in wrapping the DataOutput...InputSplits are very inconsistent in how they serialize themselves. Many attempt to close the stream.