[cppmyth] recording.priority should be signed

- Update DTO 75, 82
[cppmyth] buffering
[cppmyth] LiveTV: dummy file

Backend 0.28-pre crash if we try to open dummy file for transfer.
Here i open transfer after file is filled.
[mythtv] Bump version 1.9.16
[cppmyth] buffering: request more
[mythtv] Bump version 1.9.17
[cppmyth] Cleanup code for thread safety
[cppmyth] DeleteRecording: force and forget options
[mythtv] Fix optional flags to delete and forget recording
[mythtv] Cleanup FileTypes and cache management
[cppmyth] Cleanup inheritance

- Hide base members in final classes
- Control: Unify protocol and API services
[mythtv] cppmyth update

- New interface for Myth::Control
- Handle connection lost/restored
[cppmyth]  const-correctness
 [cppmyth] Unify services
[mythtv] Unify services
[cppmyth] GetSetting by hostname
[cppmyth] GetSetting by hostname: Control
[mythtv] Open recording from slave backend

Get setting for IP/IP6 and Port.
[mythtv] Review capabilities

Remove obsolete code
[cppmyth] New API services with protocol 82

- DeleteRecording replaces protocol command DELETE_RECORDING
- UnDeleteRecording replaces protocol command UNDELETE_RECORDING