Added controllers stopper

This node takes care about taking down and restarting controllers based on
the robot's state.

Closes #48

controller_stopper/src/controller_stopper_node.cpp

@@ -0,0 +1,30 @@
+// this is for emacs file handling -*- mode: c++; indent-tabs-mode: nil -*-
+
+// -- BEGIN LICENSE BLOCK ----------------------------------------------
+// -- END LICENSE BLOCK ------------------------------------------------
+
+//----------------------------------------------------------------------
+/*!\file
+ *
+ * \author  Felix Mauch mauch@fzi.de
+ * \date    2019-06-12
+ *
+ */
+//----------------------------------------------------------------------
+
+#include <ros/ros.h>
+
+#include <controller_stopper/controller_stopper.h>
+
+int main(int argc, char** argv)
+{
+  // Set up ROS.
+  ros::init(argc, argv, "controller_stopper_node");
+  ros::NodeHandle nh;
+  ros::NodeHandle priv_nh("");
+
+  ControllerStopper stopper(nh);
+
+  ros::spin();
+  return 0;
+}