Merge pull request #39 from shahaan/mcc-nectar

I'm merging this one, but I'd like a couple of extra features down the line. In particular I would like the dynamic inventory to take as an argument the heat stack name or ID and walk down the tree from there (so that I can run two independent clusters out of the same tenancy). I like the use of ansible_host_group and ansible_ssh_user in the metadata.