[geometry] Bugfix in rescaling, points may not be const& (of course)
They were initialized from local variables and returned
[geometry] Let rescale derive from not_implemented as is new style
[geometry] Collinear touch now also uses new unified method
This fixes the holes_intersect_and_touch case
NOTE: method should now be renamed, not ...two_intersection_points
[geometry] Modified #clips, caused by fix in touch
(note: this was modified to 4 in 9a9efcff89fb081babfc31f8a34cfb2c80386974,
18 dec 19:19:10 so this is effectively a reversal)