Feature Request: unlock only takes a lock, not a resource name.

[ar4hc]

i'd like to be able to unlock() using the resource, too. Now only using the returned lock from lock() works.
I'd prefer a solution like is_locked() that takes both kinds of argument.

Background:

i want to use locks in an REST API, so the caller of unlock() shouldn't (and can't) get the lock object from lock()

[gtmanfred]

closed by #84