MAHOUT-1604, MAHOUT-1541 changes all reference to positon in the CLI to columns
MAHOUT-1500: Code cleanup and javadocs closes apache/mahout#50
MAHOUT-1615: SparkEngine drmFromHDFS returning the same Key for all Key,Vec Pairs for Text-Keyed SequenceFiles. this closes apache/mahout #52
Revert "MAHOUT-1615: SparkEngine drmFromHDFS returning the same Key for all Key,Vec Pairs for Text-Keyed SequenceFiles. this closes apache/mahout #52"

This reverts commit 034afd61126660b6f44b232fdf3e1dd9d1a79708.