Retry request 5x when the response is in the 4xx range before raising an exception.
Merge remote-tracking branch 'spilgames/master' into retry_on_4xx_status_code

Conflicts:
	README.rst
Merge pull request #31 from brocaar/retry_on_4xx_status_code

Retry request 5x when the response is in the 4xx range before raising an exception.