Added path follower to ratslam demo app. This closes #4.

* [mod] modified ratslam launch to start ratslam's naive path follower

launch/ratslam.launch

@@ -5,24 +5,32 @@
   <node name="RatSLAMLocalViewCells" pkg="ratslam_ros" type="ratslam_lv"
         args="$(arg config_path)/ratslam.txt"
         required="true" >
-    <remap from="image" to="cozmo_camera/image" />
+    <remap from="image"         to="cozmo_camera/image" />
     <param name="lvm_file_path" value="$(arg config_path)/ratslam-latest.blvm" />
   </node>
 
   <node name="RatSLAMPoseCells" pkg="ratslam_ros" type="ratslam_pc"
         args="$(arg config_path)/ratslam.txt"
         output="screen"
         required="true" >
-    <remap from="odom" to="cozmo/odom" />
+    <remap from="odom"          to="cozmo/odom" />
     <param name="pcn_file_path" value="$(arg config_path)/ratslam-latest.bpcn" />
   </node>
 
   <node name="RatSLAMExperienceMap" pkg="ratslam_ros" type="ratslam_em"
         args="$(arg config_path)/ratslam.txt"
         output="screen"
         required="true" >
-    <remap from="odom" to="cozmo/odom" />
+    <remap from="odom"          to="cozmo/odom" />
     <param name="map_file_path" value="$(arg config_path)/ratslam-latest.bmap" />
   </node>
 
+  <node name="path_follower" pkg="ratslam_ros" type="path_follower.py"
+        output="screen" >
+    <remap from="cmd_vel" to="platform_control/cmd_vel" />
+    <remap from="path"      to="cozmo/ratslam/ExperienceMap/PathToGoal" />
+    <param name="min_lin_vel" value="0.05" />
+    <param name="max_lin_vel" value="0.20" />
+  </node>
+
 </launch>