Update (Backend)

- Refactored Code
 - FileModel.java
 - ImageModel.java
 - ObjectMouseListener.java
 - PointModel.java
 - ShapeModel.java
 - TextboxModel.java
 - WebpageModel.java
 - ColorPallet.java
 - ToolButton.java
 - ToolEraserView.java
 - ToolMarkerView.java
 - ToolModel.java
 - ToolPictureView.java
 - ToolShapeView.java
 - ToolTextView.java
 - ToolView.java
 - ToolWeb.java