nodes can now be connected through the node editor

nodes/nodeedge.cpp

@@ -0,0 +1,21 @@
+#include "nodeedge.h"
+
+#include <QDebug>
+
+#include "effects/effectrow.h"
+
+NodeEdge::NodeEdge(EffectRow *output, EffectRow *input) :
+  output_(output),
+  input_(input)
+{
+}
+
+EffectRow *NodeEdge::output()
+{
+  return output_;
+}
+
+EffectRow *NodeEdge::input()
+{
+  return input_;
+}