Address use of spaces instead of tabs in line indentation
Address a few cases where the response from an IGD wasn't present or unrecognised response received. Bail out and do not attempt to recover.
Added a UPNP_DeletePortMapping() call to remove the UPnP entry after it's no longer needed.
Switch the port forwarding over the UDP protocol (the 'unrealiable TCP' in the FS2Open code base).
Merge remote-tracking branch 'echelon9/upnp-support' into upnp-support