The initial priming now does not assume anything about bed width and always uses the space it has
In case of circular beds it places the priming lines along the diameter
Custom beds are not supported (they are treated as circular with no extra checks whether it is sane)
Slight refactoring of the WipeTower class (constructor now gets reference to PrintConfig and not the individual values, same with set_extruder). This was legacy from times when the wipe tower was meant to be abstract and independent on the rest)
- abstract class WipeTower and its descendant WipeTowerPrusaMM were merged into a single (non-abstract) WipeTower class
- all uses of WipeTower::xy struct were replaced by Eigen Vec2f (it is no longer necessary to be independent on libraries that PrusaSlicer uses)
- the WipeTowerPrusaMM.hpp/.cpp will be renamed in the next commit (hopefully it will retain its git history that way)
The priming extrusions were handled separately from the rest of the wipe tower toolchanges. In order to be able to use the logic from previous commit for them (custom toolchange gcodes etc), some unpleasant code shuffling was needed
