AP_Notify: fixed LED colour for no-GPS and armed
AP_Arming: allow checking of pre-arm without reporting

useful for updating AP_Notify LEDs
Plane: update AP_Notify flags for arming state
Plane: improve LOG_BITMASK docs
AP_Math: added equality operator for VectorN
AP_Notify: reduce the latency in the main task of LED updates

the ioctl now gets called in a IO timer callback