Update status section to indicate HOT is supported
Update status section to indicate HOT is supported

This updates the status section of hot_spec.rst to indicate
Icehouse is supported and reliable, and indicate that future
versions will allow versioning of the template language.

Change-Id: I70455f71362babcea746831dd730f8c33ef51745
Closes-bug: #1304145

dims/heat,rh-s/heat,takeshineshiro/heat,dragorosson/heat,maestro-hybrid-cloud/heat,gonzolino/heat,gonzolino/heat,pratikmallya/heat,rh-s/heat,srznew/heat,pshchelo/heat,takeshineshiro/heat,noironetworks/heat,jasondunsmore/heat,rdo-management/heat,miguelgrinberg/heat,redhat-openstack/heat,srznew/heat,dragorosson/heat,cwolferh/heat-scratch,openstack/heat,cryptickp/heat,pratikmallya/heat,openstack/heat,steveb/heat,maestro-hybrid-cloud/heat,redhat-openstack/heat,miguelgrinberg/heat,pshchelo/heat,cryptickp/heat,noironetworks/heat,steveb/heat,rdo-management/heat,dims/heat,cwolferh/heat-scratch,jasondunsmore/heat