Adding initial support for connection string.

Change-Id: I8e60030809510e79212631cdea1324202ece6a7d
Reviewed-on: http://review.couchbase.org/40332
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>