CR-10s bed testing

Simple set of 5 20x20mm tiles, approximately over the height adjustment points on the CR10s and the middle of the bed.

If you slice this you should print single layer squares, which allow you confirm you bed is level.

At a given corner if the layer is too thin lower the bed in that corner, if the surface is bumpy raise the bed in that corner. If your corners a ok, but the centre is no good you either need to realign your other axes relative to the bed or change your bed.

27/March/2020: Added mylevel_test_5_squares_full_line.stl as requested by a user.