Optional README file for overall goals and features

Copied goals from John's ppt

Change-Id: If6166098f56227fbc9aa114ab0f4d77ad1542656
Reviewed-on: http://review.couchbase.org/34934
Reviewed-by: John Liang <john.liang@couchbase.com>
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Pratap Chakravarthy <prataprc@couchbase.com>
Reviewed-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>
Tested-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>