Stopwatch: added restart() method

src/storm/utility/Stopwatch.cpp

@@ -55,6 +55,11 @@ namespace storm {
             isStopped = true;
         }
         
+        void Stopwatch::restart() {
+            reset();
+            start();
+        }
+        
         bool Stopwatch::stopped() const {
             return isStopped;
         }

src/storm/utility/Stopwatch.h

@@ -66,6 +66,11 @@ namespace storm {
              */
             void reset();
             
+            /*!
+             * Reset the stopwatch and immediately start it
+             */
+            void restart();
+            
             /*!
              * Retrieves whether the watch is stopped.
              */