AP_Math: added vectorN class, and index checking
AP_Math: prevent transpose usage error in matrix API
AP_Math: add const to quaternion API
AP_HAL: added time_shift() scheduler API

used for log replay
HAL_Linux: implement time_shift() API
AP_GPS: allow HIL GPS to show no lock
AP_Compass: added vector compass setHIL method
px4: fixed IO build