- added a bilinear interpolation calculation class from: https://github.com/pmav99/interpolation
- in CNCJob UI Autolevelling: made sure that the grid can't have less than 2 rows and 2 columns when using the bilinear interpolation or 1 row and 1 column when using the Voronoi polygons
- in CNCJob UI Autolevelling - Voronoi polygons are now plotted
- in CNCJob UI Autolevelling - adding manual probe points now show some geometry (circles) for the added points until the adding is finished