Added threadpool for making callbacks so main process thread cannot be  blocked in app code.  Some simplification of the internal delivery  machinery for consistent delivery in separate thread.
Added threadpool for making callbacks so main process thread cannot be 
blocked in app code.  Some simplification of the internal delivery 
machinery for consistent delivery in separate thread.



ebollens/ccnmp,ebollens/ccnmp,cawka/ndnx,svartika/ccnx,cawka/ndnx,cawka/ndnx,cawka/ndnx,svartika/ccnx,ebollens/ccnmp,svartika/ccnx,svartika/ccnx,svartika/ccnx,svartika/ccnx,cawka/ndnx,ebollens/ccnmp,svartika/ccnx