Issue38 - break proprietary ping into proper component

* removed gcm cruft from app
* added "default" for LoadExtensibleSection to allow for less app preconfig

@bbangert I think I grok what you've done. r?
I'm tempted to say that multiple Proprietary Pings is a future enhancement and for now, we support only one. The current thinking was that GCM would be far more likely to land before UDP, thus why GCM is a tad more fleshed out than UDP.

I'm also not really a fan of breaking these out into discrete sections, partly because of the impact to LoadApplicationFromFileName(). I can see it getting overloaded with components quickly. It may make sense to make the proprietary ping function a fully external service so that we don't have to deal with the restrictions go requires.