Respond to a `205` status code by returning the current resource.
Respond to a `205` status code by returning the current resource.

This alters the post() signature a bit since the last alpha, and forces
people to be more explicit. On the bright side, it means that users can
skip the 'if (res === null)` guard every time they use it.

evert/restl,evert/ketting,evert/ketting