urlresolver - rough patch for discussion

@SharkHunter  - this is very roughly what I have in mind, but it does have some logical quirks still.  Basically the resolver gets to inspect/attach directly to the DLNAResource, and maybe even retrieve stuff it attached to it earlier. This lets us populate folders faster since we can go ahead and create the item when all we know is name and thumb and leave everything else for later (a lot of xbmc items come in this 2-stage way for instance).