API support for Environments

Support "Environment" section in the create/update body.
We the roll up the parameters and the environment and send
that as json using the rpc "params" argument. So no changes
to the rpc layer are needed. The engine knows how to deal
with both formats in the Environments class.

blueprint envirnonments
Change-Id: I6d6085d5c052a5f9115ecd46891b00d2fad4d1db
Cleanup the doc strings in heat/rpc/client.py

Change-Id: Ia760937f729a1aa17d84c48054cb143bf6891bfd
Merge "API support for Environments"
Merge "Cleanup the doc strings in heat/rpc/client.py"