Modify feet to locate with four prongs instead of two tabs

Inserting the bands with the band tool is a frequently noted as an assembly issue. Part of this could be because it is a tight fit to get the band tool and the band through the slots in the feet. It is important to get the bands evenly stretched on both sides to avoid breaking, and this is hindered when the band is trapped between the tool and the foot.

Splitting the location lugs on the feet into four prongs gives more space for the band insertion tool and the band to pass through.