Cleanups in rabbitpy.io

- Log exceptions before adding to queue to get traceback
- Add  back support for Basic.Return
- Fix the _add_frame_to_queue method
- change to static methods where possible
Misc cleanup

- Cleanup variable names overriding modules
- Cleanup whitespace
- Use static methods where appropriate
- Reorder methods a bit
- Reflect API changes in rabbitpy.channel
Cleanup of channel

- Cleanup where local variables overwrote module names
- Note unused arguments
- Don't try and do a RPC close if already closed
- Add methods for rabbitpy.io to invoke directly for Channel.Close and Basic.Return
- Rename _open to open
- Reorder methods a bit
- Move to static methods where possible
- Allow for empty message bodies and malformed ContentHeaders
Channel0 cleanup

- Don't have mutable method arguments
- rename self._properties to self.properties
- Change to static methods where possible
Cleanup rabbitpy.base
Update docs and use a static method
Bump the rev, change from README.md to README.rst