MASTER: Add parameter to tell ROS to use simulated time in sitl.launch

ap_master/launch/sitl.launch

@@ -18,6 +18,9 @@
   <arg name="bag" default="0" />    <!-- Generate ROS bag files -->
   <arg name="verify" default="0" /> <!-- Param/fence/rally/wp verify -->
 
+  <!-- Use simulated time -->
+  <param name="/use_sim_time" value="true" type="bool"/>   
+
   <!-- Launch master with modified args and optional namespace -->
 
   <include file="$(find ap_master)/launch/master.launch" ns="$(arg ns)" >