Add Closest Operation

[crhallberg]

Finds a specified number of points closest to a given point.

Uses a sort of binary search with the radius of a Circle query. Using Rectangle may be more performant for finding a single closest point but produces inaccurate results for operations expecting multiple detected points.

• Handle ties in the cases of:
  • Equidistant points
  • Identical points
• Write tests

For the handling of ties, I specified a limit on the number of checks and return a slice of the current query if we reach it.

[shiffman]

Merging!

[crhallberg]

I was working on more optimizations of this because I started working with a huge dataset. It might make sense to wait for the save-load PR so I can contribute that data tree as well.

[shiffman]

(invite sent btw!)