mavwp: added support functions for fence editing
pymavlink: added add_latlonalt() for waypoint map editing
APM: changed SIMSTATE to use int32_t lat/lon

this allows us to test the full accuracy of GPS drivers. Note that
SIMSTATE is only used by mavproxy at the moment, so changing this
doesn't break anything else
mavutil: changed mavlink_connection() to support open retries on TCP

this avoids race conditions in SITL startup
mavextra: added airspeed_ratio() and improved gps velocity
pymavlink: fixed generator to run from installed package
messages: added MAV_CMD_DO_SET_ROI

this is used by ArduCopter