Additions:
- Add sub_channels
- Handle sub channel in Baichuan abilities
- Add sub_channel to baichuan api_version
- Add sub_channel to baichuan capabilities
- Add internal _add_capability function
- Add sub_channel to capabilities
- Add PTZ sub channel capabilities
- Add sub_channel to baichuan send and set_ptz_command
- Add sub_channel to set/get_ptz_guard and ptz_callibrate
Bug fixes:
Optimizations:
Full Changelog: 0.21.13...0.21.14