Blender Git Loki

UV: remove selection threshold for nearby coordinates

Internally UV selection considered close UV's to be connected.
While this could be convenient in some cases,
it complicates logic for more advanced selection operations that
need to check when UV's should be considered part of the same vertex
since simple threshold checks would give different results depending
on the order of UV's tested.

Users must now run "Merge by Distance" instead of relying
on this selection threshold.