Merge pull request #306 from datastax/wip-265-table-writer-error-reporting

Add logging of error message when asynchronous task fails in AsyncExecut...
Added forgotten entry in CHANGES.txt.
Merge branch 'b1.0' of github.com:datastax/spark-cassandra-connector into b1.1
Merge branch 'b1.0' of github.com:datastax/spark-cassandra-connector into b1.1

Conflicts:
	CHANGES.txt