Better satin borders with OpenCV

[Filipssh]

Replaced satin borders convex hull method with OpenCV's contour finder.

Features:

• Accurate borders wrapping the shape of the patch
• Adjustable small gap bridging and path smoothing using dilate/erode filters
• Support for individual borders in disjoint shapes

Examples:

[mariobodemann]

Hey,

thank you for your contribution, it'll take me a couple of days to get back to you, but in general it looks okay.

Two random questions:

a) How much of that code is done by AI and how much by you?
b) While the borders look very nice now, I'm seeing a bit more irregularity to it, the zig zag stitches look a bit more jaggered. Do you understand why?

Thanks again.