Since sparse matrices now support a isTransposed flag for row major data, DenseMatrices should do the same.

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #5455 from MechCoder/spark-6845 and squashes the following commits:

525c370 [MechCoder] minor
004a37f [MechCoder] Cast boolean to int
151f3b6 [MechCoder] [WIP] Add isTransposed to pickle DenseMatrix
cc0b90a [MechCoder] [SPARK-6845] Add isTranposed flag to DenseMatrix