Encode member collection handler types in the bit pattern for the handler

[lifflander]

What Needs to be Done?

Right now, in {send,broadcast}UntypedHandler we pass around a boolean member to distinguish the handler type (member vs. function) on the send and receive side after the handler is registered. That bit can easily fit in the 64-bits for HandlerType. Encode it, remove it from messages, and from the interface.

[lifflander]

@jstrzebonski Can you work on this next? Right now in theCollection API, we have a boolean that gets passed around a lot the encodes whether the handers is on a member or function. I would like to include this in the handler bit pattern somehow, so we don't have to explicitly store this state everywhere.