More verbose debug logging of UPnP SOAP requests
Parse UPnP service ID from root description and expose it to consumers
Variable naming clarification
Fix UPnP log spam on networks without UPnP IGDs (see #893)

We should only run the UPnP port mapping renewal routine if the initial
discovery and configuration succeed. This commit applies that logic.
UPnP discovery fix for devices that send multiple response packets

Fix UPnP discovery and port mapping issues reported in #896
Merge pull request #898 from cqcallaw/upnp

Various UPnP updates