use strings to connect nodes

This makes the node system somewhat more high-level with the intent of making
working with them far more flexible and stable. By making the architecture more
abstracted, it becomes far less rigid which should allow us to do even more
with it and make it much less crash prone.

app/node/input/time/timeinput.cpp

@@ -51,8 +51,10 @@ QString TimeInput::Description() const
   return tr("Generates the time (in seconds) at this frame");
 }
 
-NodeValueTable TimeInput::Value(NodeValueDatabase &value) const
+NodeValueTable TimeInput::Value(const QString &output, NodeValueDatabase &value) const
 {
+  Q_UNUSED(output)
+
   NodeValueTable table = value.Merge();
 
   table.Push(NodeValue::kFloat,

app/node/input/time/timeinput.h

@@ -38,7 +38,7 @@ public:
   virtual QVector<CategoryID> Category() const override;
   virtual QString Description() const override;
 
-  virtual NodeValueTable Value(NodeValueDatabase& value) const override;
+  virtual NodeValueTable Value(const QString& output, NodeValueDatabase& value) const override;
 
   virtual void Hash(QCryptographicHash& hash, const rational& time) const override;