Refactor Undo and SaveLoad from disk.

script/pages/editor/model/UndoStack.js

@@ -0,0 +1,41 @@
+// Undo Stack
+
+
+
+function UndoStack(maxUndoStackSize) {
+    this.undoStack  = [];
+    this.maxUndoStackSize = maxUndoStackSize;
+}
+
+UndoStack.prototype.PushToStack = function(actionName, dataToSave)
+{
+    var object        = {};
+    object.actionName = actionName;
+    object.data       = dataToSave;    
+    
+    this.undoStack.push(object);
+
+    while (this.undoStack.length > this.maxUndoStackSize)
+    {
+        this.undoStack.shift();
+    }
+}
+
+UndoStack.prototype.Undo = function()
+{
+    if (this.IsUndoStackEmpty())
+        return null;
+    
+    var state  = this.undoStack.pop();
+    return state.data;
+}
+
+UndoStack.prototype.ClearUndoStack = function()
+{
+    this.undoStack = [];
+}
+
+UndoStack.prototype.IsUndoStackEmpty = function()
+{
+    return (this.undoStack.length <= 0);
+}