Shape class added.
StrokeShape class.
CanvasView getting data from CanvasViewDatasource now.
Prerendering and line splitting temporary disabled.
Prerendering implemented in CanvasView.
CanvasView refactored.
Painting interface redesigned.
PaintingDelegate, undo/redo buttons.
EditorViewController refactored.
Painting inherits UIDocument, undo/redo partially implemented.
Undo/redo implemented.
Painting is no longer an UIDocument.