NAT-PMP modules improvement

There really isn't anything new here.  This is just a cleanup of the modules to make them faster, cleaner and more useful by default.  This was achieved by:

* Moving more of the core functionality into the NAT-PMP mixin
* Updating natpmp_map to support mapping multiple ports at once and providing a useful set of ports to start with
* Updating natpmp_portscan to destroy mappings once at the beginning rather than once per port to side-channel scan
* Updating natpm_portscan to only report_ open ports -- reporting the closed ports is largely useless and is just cruft in the db
* Cleanup of all console logging