exchange() getter for Message objects
Merge pull request #40 from mcurtiss/mc-exchange

exchange() getter for Message objects
Add integration tests
Fix new integration tests in Python 3
Fix the integration tests for Python2 & 3
Clean up rabbitpy.Message

- Break out some functionality in the constructor to stand alone methods
- Clean up order of operations in __init__
- Add some test coverage (more coming)
- Raises a KeyError on creation if an invalid property is passed in
- Cast different types of timestamp values to datetime.datetime
- Break out the invalid properties list to a standalone method
- Reorder methods to have private methods at the end
Merge branch 'master' of github.com:gmr/rabbitpy into cancel_consumer

* 'master' of github.com:gmr/rabbitpy:
  Clean up rabbitpy.Message
  Fix the integration tests for Python2 & 3
  Fix new integration tests in Python 3
  Add integration tests
  exchange() getter for Message objects
fix blocking consumer