RPLProactor - rename function 'DeliverToApplicationLooped'

Both the function name and the comment for it were misleading.
This function does a one-shot delivery - not a looped delivery.
Looped delivery is not a good idea because it would not guarantee
for the application that each RPLProactorWait call returns and
allows the application to do a shutdown at will.
Cleanup:  fix incorrect comment in proactor
RPLProactor:  move forward declarations into common header