Provide a more explicit message when dealing with exception from the SoT.

src/roscontrol-sot-controller.cpp

@@ -935,11 +935,25 @@ void RCSotController::one_iteration() {
   /// Generate a control law.
   try {
     sotController_->nominalSetSensors(sensorsIn_);
+  } catch (std::exception &e) {
+    std::cerr << "Failure happened during one_iteration(): "
+              << "when calling nominalSetSensors " << std::endl ;
+    std::cerr << __FILE__ << " " << __LINE__ << std::endl
+              << e.what() << std::endl;
+
+    throw e;
+  }
+  try {
     sotController_->getControl(controlValues_);
   } catch (std::exception &e) {
+    std::cerr << "Failure happened during one_iteration(): "
+              << "when calling getControl " << std::endl;
+    std::cerr << __FILE__ << " " << __LINE__ << std::endl
+              << e.what() << std::endl;;
     throw e;
   }
 
+
   /// Read the control values
   readControl(controlValues_);