Example for cassandra CQL read/write from spark

Cassandra read/write using CqlPagingInputFormat/CqlOutputFormat

Author: anitatailor <tailor.anita@gmail.com>

Closes #87 from anitatailor/master and squashes the following commits:

3493f81 [anitatailor] Fixed scala style as per review
19480b7 [anitatailor] Example for cassandra CQL read/write from spark
Small clean-up to flatmap tests