AP_Compass: added vector compass setHIL method
AP_NavEKF: initial test sketch for NavEKF
AP_NavEKF: added dataflash log reader

this gives log playback into HIL
Cleaned formatting and explicitly defined numerical values and trig operators as floats
AP_NavEKF: cleanup header, adding comments
AP_NavEKF: added euler angle functions
AP_NavEKF: try running EKF on log data
AP_GPS: allow HIL GPS to show no lock
AP_HAL: added time_shift() scheduler API

used for log replay
HAL_Linux: implement time_shift() API
AP_NavEKF: fixed compass declination, baro cal and time shift

now runs much faster
AP_NavEKF: added plot.dat output
debug updates
debug updates