Optimize drill path

[abetusk]

Drill paths are unoptimized potentially requiring a lot extra time to cut. Even rudimentary path optimization would probably help a lot.

Depth cut paths can't be optimized as they must cut material out but the entry and exit points can be chosen. The 'air path' is the main point of optimization. Even choosing the entry and exit points of the depth cut as fixed and then optimizing the time the spindle is moving without cutting would probably have large gains.

The 'correct' way to do this is to throw a Travelling Salesman Problem solver at it. There might be good enough gains by creating a Voronoi region from the entry points to cuts and greedily choosing something nearby.

Bolting on a TSP solver is potentially heavy duty so the scope of this tool needs to be considered. There might be other programs to solve this issue rather than putting it in here.