replace handles with (namespace, identifier) tuples
Submitted by Simon McVittie
Assigned to Telepathy bugs list
The strangeness of handles is justified by performance and normalization considerations for contacts, but not for all other handle types.
In Telepathy 1.0 (Bug #23148), fixing Bug #23151 will allow us to discard the Room handle type, and fixing Bug #21787 will allow us to discard the List and Group handle types.
Having done that, we can remove Channel.TargetHandleType altogether - it will implicitly be (TargetHandle == 0 ? NONE : CONTACT).