Fallback to requests=0.14 using "requests-transition"

If py4chan is installed as is, it will also install "requests=1.xx". This version of requests is completely incompatible with "requests=0.14", which py4chan uses.

The full solution would be to fix py4chan to use the new version of requests. 

However, as a quickfix for anyone using the py4chan right now, I am submitting this pull request with the ["requests-transition"](https://pypi.python.org/pypi/requests-transition) (read it for more information) library as a dependency.