corregido error por cambio en IribaseAlgorithm para ubuntu 18.04 y ROS-melodic

src/diff_platform_simulator_alg_node.cpp

@@ -4,7 +4,8 @@ DiffPlatformSimulatorAlgNode::DiffPlatformSimulatorAlgNode(void) :
   algorithm_base::IriBaseAlgorithm<DiffPlatformSimulatorAlgorithm>()
 {
   //init class attributes if necessary
-  this->loop_rate_ = 50;//in [Hz]
+  //this->loop_rate_ = 50;//in [Hz] // for ROS indigo or hydor and ubuntu 14.04
+  setRate(50);
   
   this->public_node_handle_.getParam("robot", this->tf_prefix_);
   this->odom_id_           = "/" + this->tf_prefix_ + "/odom";