multicam: refactor to heavily optimize multicam monitor retrieval

app/node/input/multicam/multicamnode.h

@@ -20,8 +20,6 @@ public:
 
   virtual ActiveElements GetActiveElementsAtTime(const QString &input, const TimeRange &r) const override;
 
-  virtual ShaderCode GetShaderCode(const ShaderRequest &id) const override;
-
   virtual void Value(const NodeValueRow& value, const NodeGlobals &globals, NodeValueTable *table) const override;
 
   virtual void Retranslate() override;
@@ -29,8 +27,6 @@ public:
   static const QString kCurrentInput;
   static const QString kSourcesInput;
 
-  void SetMonitorMode(bool e) { monitor_ = e; }
-
   int GetCurrentSource() const
   {
     return GetStandardValue(kCurrentInput).toInt();
@@ -54,9 +50,6 @@ public:
     return col + row * total_cols;
   }
 
-private:
-  bool monitor_;
-
 };
 
 }