removed the duplicate definitions (closes #120)
linked states to their definitions (closes #181)
CallState is now free form (closes #181)
Moved CallDirection enum (closes #182)
Moved DisconnectReason to CallHistory appendix (closes #183)
Removed error steps (closes #164)
Fixed up how disconnecting happens.

part of #172
Moved DisconnectReason emum (closes #186)
TCallControl becomes telephony service (closes #172)