updated import to houston library
Added new classes for abstraction.

- Added 3 new classes Repo, System and Channel
  All three channels masquerade as dicts with relevant info.

- Channel class also has methods to interact with channels on the server.

- moved some functions from the Spacewalk Class to channel class as more
  pertinant there, some methods removed entirely as now accessible through
  dictionary syntax.

- updated houston to use new classes and methods.
Merge branch 'master' of https://github.com/peteches/Houston