offset, roundPrecision, and miterLimit

[phtj]

It would be useful to add a comment to the docs to explain that if scaling is being applied, then offset and roundPrecision need to be scaled, but miterLimit should not be scaled.

It is explained in the js clipper docs: miterLimit is "the maximum distance in multiples of delta that vertices can be offset from their original positions before squaring is applied". But it took me a while to figure out what was going on.