CommandHandler.java
       [CommandHandler.clear, 29] - Public Method
       [CommandHandler.removeObserver, 19] - Public Method

CommandHistory.java
       [CommandHistory.getRedoStack, 27] - Public Static Method
       [CommandHistory.getUndoStack, 30] - Public Static Method
       [CommandHistory.shapesDeleted, 13] - Public Static Variable
       [CommandHistory.shapesGrouped, 15] - Public Static Variable