- add conversation thread type to conversation thread
https://github.com/openpeer/op/issues/173
Merge branch 'feature-20141215-fix-conversation-glitches' of https://github.com/openpeer/op-core-cpp into feature-20141215-fix-conversation-glitches

Conflicts:
	openpeer/core/IConversationThread.h
	openpeer/core/cpp/core_ConversationThread.cpp
	openpeer/core/internal/core_ConversationThread.h