Documentation: Sorting strategies

ToDo: we need some more documentation (or integrate this as help inside the laser profile settings)

FILE: elements are in the order they are saved in the file (usually the order they are stacked from "behind" to "front"). Good for LaserScript.

NEAREST: as fast as possible (minimal ways between two paths), but outside paths can be cut before inside ones. If you use this for cutting, there may be a problem: Big outside paths can be cut before small ones, so a big piece of material falls out or moves and then the small inside parts may not come out correctly.

INNER_FIRST: (recommended for most cases): cuts inside elements before the outside ones (heuristic comparison, not 100% perfect). If the paths are split into many unconnected segments, which can happen when importing DXF files, it can become very slow.

SMALLER_FIRST: compares elements by the area of the bounding-box. Example: A wooden piece with many small holes. For bent materials like wood, it is often necessary to cut smaller parts a second time, because the focus did not match 100% - so with this sorting strategy, you can cut the small holes again and stop the job then. For most simple projects, the strategy should be very similar to INNER_FIRST. It only works when the paths are connected, so a rectangle must not be four individual line objects.