Support simple payload to force fetch and deploy

This is to support simple payload as little as url to initiate the fetch and deploy from any SCM.   This would allow an simple on-demand fetch.  This in a way lets us do a unit test on fetch and deploy w/o initiating payload from SCM.   Other details ...

(1) The Deployer is the host name of the url.  
(2) Optional is_hg for using Mercurial client.
(3) Cleanup properties that are no longer used.