improve readme content
improve readme content

Add Template samples repo to README, make sure everybody knows.

Change-Id: Ifbe73cae4c9b7bf3a2d1a17bda6db4ccfab07ab0

openstack/heat,dims/heat,steveb/heat,jasondunsmore/heat,openstack/heat,steveb/heat,dims/heat,dragorosson/heat,noironetworks/heat,noironetworks/heat,cwolferh/heat-scratch,maestro-hybrid-cloud/heat,gonzolino/heat,jasondunsmore/heat,gonzolino/heat,maestro-hybrid-cloud/heat,cwolferh/heat-scratch,dragorosson/heat