This change will allow mqtt messages simpler by allowing something like
`publish cmnd/ir-bridge/IRHVAC {"Power": "On"}`.
The simpler format is required for working with mqtt clients like
iotMQTTPanel or similar on android.
Limitations:
- Requires full message be sent at-least once. I work around this with
a `system#boot` rule
- Gets messy with multiple devices. I have only one AC per room, and
this doesn't doesn't interfere with other IR devices.
TODO:
- [ ] Change the build flag `INCREMENTAL_IRAC`to a `SetOption`
- [ ] Persist `irac_prev_state` across reboots.
- [ ] Support multiple devices.
2f616eef2c