Add a proxier that does what the bouncer does, but proxies requests instead of bouncing them.

The current bouncer tests are more end-to-end tests. We should keep these but also add tests for the individual bouncer request handler methods.

See #1 for the initial bouncer work.
Looks like the [default](https://github.com/fiorix/cyclone/blob/master/cyclone/web.py#L114-L115) is all the methods anyways, sounds like a bug (either that or I'm doing something wrong).