Copter: add parameter description for LOG_BITMASK

Should allow a dropdown in the GCS so it can be set more easily without
going into the cli
Copter: typo in LOG_BITMASK param description
added ch7 option to reset yaw back to what it was when quad was armed
indent correct
indent correct again
Copter: RESETTOARMEDYAW order and comments

We should keep the order in the case statement the same as the #define
order.
Rover: add parameter description for LOG_BITMASK
Plane: add parameter description for LOG_BITMASK
Copter: param update for AP_Baro and AP_Scheduler
Plane: param update for AP_Baro
TradHeli: add parameter descriptions

small formatting changes too
AP_AHRS: add parameter descriptions
Copter: minor parameter description fixes
Rover: added @User: Standard for battery capacity
Copter: fixed parameters to pass new script
scripts: don't push parameters XML on any errors
AP_InertialSensor: fixed parameter markup
param_metadata: fixed parameter parsing for multi-parameter objects

also adds more error checking
autotest: check te parameter doc parsing in autotest
Copter: add Fence to CH7/CH8 param description