Send battery status (ghst_telemetry). Apply factors to show correct values of volts, amps and mAh. Change ghost protocol code to follow more MISRA C++ guidelines.
- always check system field for validity
- reject any data outside of "servo position" valid range from Spektrum specification
- properly support XPlus channels (12+)
- debug message if channel count changes
Some of these perf counters were useful during initial development, but realistically aren't needed anymore, some are redundant when we can now see the average interval from `work_queue status` and some of them simply aren't worth the cost at higher rates.
* adds a work_queue systemcmd that will bring a tree view of all active work queues and work items
* WorkQueues now track attached WorkItems and will shutdown when the last WorkItem is detached
A board only needs to define:
#define RC_SERIAL_PORT "/dev/ttyS4"
Then it can optionally define one or more of the following:
#define RC_SERIAL_SWAP_RXTX
#define RC_SERIAL_SINGLEWIRE
#define RC_INVERT_INPUT(_invert_true) px4_arch_gpiowrite(GPIO_SBUS_INV, _invert_true)
