Customizable, Stackable Box for Parts Collection v3.1.

The magnet was removed, just using edge grip for cover and stacking. The stacking is fully compatible with v2.0.

See also: Customizable Toolbox v1.0

Changes on v3.1:

• Support partition customizing up to 4 partitions (adjustable each by 1/100 step)

Changes on v3.0:

• Thickness of all walls are reduced by default, so it is lighter and needs less PLA.
• Made the top edge separated from the side walls to make it stronger than walls.
• Added an angle at the bottom of the side walls to make it easy to detach.
• For the v2, the internal space was divided as three blocks of the almost the same size but now v3 has spaces of 1/2, 1/5, and 3/10.