Added Editor Properties widget at the top of every World Editor tab, made tons of backend changes to get it to work properly

src/Editor/Undo/CChangeLayerCommand.h

@@ -0,0 +1,22 @@
+#ifndef CCHANGELAYERCOMMAND_H
+#define CCHANGELAYERCOMMAND_H
+
+#include "IUndoCommand.h"
+#include "Editor/WorldEditor/CWorldEditor.h"
+#include <Core/Scene/CScriptNode.h>
+
+class CChangeLayerCommand : public IUndoCommand
+{
+    QList<CScriptNode*> mNodeList;
+    QMap<CScriptNode*, CScriptLayer*> mOldLayers;
+    CScriptLayer *mpNewLayer;
+    CWorldEditor *mpEditor;
+
+public:
+    CChangeLayerCommand(CWorldEditor *pEditor, const QList<CScriptNode*>& rkNodeList, CScriptLayer *pNewLayer);
+    void undo();
+    void redo();
+    bool AffectsCleanState() const { return true; }
+};
+
+#endif // CCHANGELAYERCOMMAND_H