It was slightly confusing to have another override for snapping while it is possible
to configure "no snapping" or "all layers" snapping mode in project anyway.
And with the nice snapping toolbar it can be also done very quickly.
Now all classes and members are either exposed to bindings or marked
as "not available in Python bindings" in the docs.
Drop test thresholds to 0. Now it should be much easier to determine
what missing members have been added which are causing test
failures.
