changed some icons and added classes for timeline view

app/node/block/block.cpp

@@ -29,3 +29,8 @@ QString Block::Category()
 {
   return tr("Block");
 }
+
+rational Block::out()
+{
+  return in() + length();
+}

app/node/block/block.h

@@ -31,6 +31,11 @@ public:
 
   virtual QString Category() override;
 
+  virtual rational in();
+  virtual rational out();
+
+  virtual rational length() = 0;
+
 public slots:
 //  virtual void Process(const rational &time) override;