Update README.rst with some small adjustments
Update README.rst with some small adjustments

Tweak the grammar a little and add in links to
the various words and projects used so that it
is more relevant to the reader.

Change-Id: Ifb425db2930c90850113e9e53c292e69af1400c8

stackforge/osprofiler,openstack/osprofiler,openstack/osprofiler,stackforge/osprofiler,stackforge/osprofiler,openstack/osprofiler