Skeleton code for MLLib extension.
Squashed list of commits

MLLib test for deep learning, logreg case

MLLib test for deep learning, logreg case

Deleted deep learning MLLIB interface.

Ugly: Add test dependency on mllib tests.

Separated mllib H2O-based extension.

Reverting changes in mllib directory.
Force mllib pom definition to produce test artifact.
WIP
Overhaul the perrier functionality

H2OContext becomes static class, not needed in most places.  Has
utilities to convert RDD & SchemaRDD -> DataFrame
H2ORDD only supports DataFrame -> lazy RDD.  No longer converts RDDs ->
DataFrames
Renaming
Finish up prostate demo

In & out of spark RDDs, plus SQL, plus an algo
Missing dependency on h2o-scala in h2o-perrier pom.xml
From typed RDD to a data frame.
Deep learning example revisited.

 - scoring return a data frame
 - prediction is validated on generated data
Merge branch 'mm_mllib_ext'

Conflicts:
	h2o-perrier/src/main/scala/org/apache/spark/h2o/H2OContext.scala
	h2o-perrier/src/main/scala/org/apache/spark/rdd/H2ORDD.scala