Marking Menu interactions

[appsforartists]

The Marking Menu demo will be a great showcase of an advanced interaction powered by Material Motion. It will need these operators:

• toPolar(): Observable<{ angle, distance }>
• toCartesian(): Observable<Point2D>
• inIncrementsOf({ size: number }): Observable<number>

and will likely be composed of many smaller interactions, such as:

• MarkingMenuItem
• MarkingMenu
• NextScreenPreview