Remove thor-scmversion stuff.
Fix machine tag system detection

- Use RightScale tag support if the rs_tag utility is in the path.
- Clean up specs for RightScale and Vagrant tag support to not use the
  MachineTag factory.
Increase memory and CPUs for kitchen tests.
Merge pull request #11 from rightscale-cookbooks/white_14_03_acu15558_check_rs_tag

White 14 03 acu15558 check rs tag