Checkpoint: trying to figure out how to structure the API.
Use Test::LWP::UserAgent

Unlike Test::Mock::LWP, this one doesn't monkey patch
so you get the full functionality of LWP (except for
actually transmitting the request).  Thanks @ether.
I think I'm happy (enough) with the API now.
Require newer Pinto::Constants

for $PINTO_SERVER_STATUS_OK
Merge branch 'topic/0.66-update'