AP_Math: fixed location build on SITL
AP_Notify: Support all GPS status flags, with status >= GPS_OK_FIX_3D notified as having a lock
AP_GPS: Support fix types of DGPS and RTK
SITL: Adding Swift Binary Protocol GPS type
Merge branch 'piksi-wip' of github.com:njoubert/ardupilot into piksi-wip