[Reviewer: Graeme] Craft logging Enhanced Node Troubleshooting 

Added PDLog infrastructure (definition in new header, craft_dcea.h) and PDLogs for http and sip.
This comment is kind of weird. I basically don't understand what it's point is. Is this supposed to be an example of what one of these logs looks like? Or is it just a helpful pointer for the order of the arguments in the constructor. I like the latter if it's true, but the title (`CPP_COMMON syslog identites`) and the inconsistent use of capitals and colons just make it look out of place.