Separate message for trajectory setpoint

msg/trajectory_setpoint.msg

@@ -0,0 +1,15 @@
+# Trajectory setpoint in NED frame
+# Input to PID position controller.
+# Needs to be cinematically consistent and feasible for smooth flight.
+# setting a value to NaN means the state should not be controlled
+
+uint64 timestamp # time since system start (microseconds)
+
+# NED local world frame
+float32[3] position # in meters
+float32[3] velocity # in meters/second
+float32[3] acceleration # in meters/second^2
+float32[3] jerk # in meters/second^3 (for logging only)
+
+float32 yaw # euler angle of desired attitude in radians -PI..+PI
+float32 yawspeed # angular velocity around NED frame z-axis in radians/second