HadoopDataSink works both for hadoop 1.2.1 and 2.2.0
add license headers
add ContextCheck to LocalExecutor; check in HadoopDataSink for output path
automatically generate a javadocs page
Add project operator to Java API
Added tests for project operator
Extended Projection.types() functions up to 22 type parameters.
Moved parameter checks from DataSet to Projection. Handing object instance instead of serializer to MapProjector.