Made some minor optimization such as:
- Avoid using "%" operation in loops, replace with a check
for index "overflow".
- Use pre-computed values for scaling feather coordinates
to 0 .. 1 space.
This allowed to reach couple of milliseconds of boost.
Another change is to use higher number of buckets (up to 512).
This doesn't took significantly more memory (like uses only 10MB
of memory for average splines) and allows to have 30-50x boost
for average splines.
Use dynamically calculated number of buckets for this, to be
sure segments would fit two buckets.
Also fixed intersection detection in some cases when edge is
shared between two buckets -- it is possible that such edge
would cross third bucket and intersect edge from there.
2c2e1775f9