implemented 'ripple to' timeline actions

app/widget/timeruler/timeruler.h

@@ -42,6 +42,8 @@ public:
 
   void SetCenteredText(bool c);
 
+  void SetSnapping(bool snapping);
+
   const int64_t& GetTime();
 
 public slots:
@@ -94,6 +96,8 @@ private:
 
   TimelinePlayhead style_;
 
+  bool snapping_;
+
 };
 
 #endif // TIMERULER_H