Ignore the first intersection of the travel path with the object from which the travel starts.
Created a new class TravelObstacleTracker, for wrapping all data structures related to lift before obstacles.
During layer change, instead of generating the gcode, generate a placeholder tag. Then at the end of layer processing replace this tag with a ramping travel move.
This solves the issue, that one does not know the starting point of the current layer where the layer change gcode would be originally generate.
The ramping layer changes uses smoothing of the ramping travel. Also it is adjusted in such a way that it increases the ramp angle when the travel is too short, to always reach the next layer.
