Added documentation on using the region features to manage multi-region clouds.
Added documentation on using the region features to manage multi-region clouds.

rackerlabs/heat-pyrax,EdLeafe/pyrax,emonty/pyos,sivel/pyrax,vikomall/pyrax,roelvv/pyrax,mandx/pyrax,briancurtin/pyrax,rackspace/pyrax,opsdisk/pyrax,ddaeschler/pyrax,naemono/pyrax,pratikmallya/pyrax,0dataloss/pyrax