added readme for matlab scripts

matlab/README.txt

+this folder contains the code for the matlab experiments.
+
+Run in matlab the scripts:
+    main_car.m
+    main_cycling.m
+for the single-trace experiments.
+
+Run in matlab the scripts:
+    main_tradeoff_car.m
+    main_tradeoff_cycling.m
+for the tradeoff experiments.