Add additional features for more complete and non-conditional mocking

- Add all_requests decorator
- If mock_method returns dict, will map keys to Response object
- Add response method that will build out a mostly populated Response object
- Add travis-ci testing config
Fix support for Python 2.6 and 3.2+
Remove incorrect assignment of response.raw
Merge branch 'master' of github.com:gmr/httmock into gmr-master

Conflicts:
	README.md
	httmock.py