SPARK-938 - Openstack Swift object storage support

This is very initial commit to initiate discussion about Spark and OpenStack Swift integration.
At this point I provided information how to setup standalone Spark cluster and connect it to Swift using Hadoop 2.3.0. Current patch can be used by all to experiment integration between Swift and Spark. 

I am working to extend this patch and future patches will contain information how to configure Spark with previous Hadoop versions and how to configure Swift for other cluster deployment of Spark.

Will glad to hear all remarks / suggestion / comments from the community.
Is this needed? Can we just put this in core-site.xml under conf? (Basically removing the configuring Hadoop section)