Blender Git Loki

Improvements to weighted tracks behavior

First thing changed by this commit is making it so
Euclidean intersection takes track weight into account
when solving minimization problem. This behaves the
same exact way as it is for BA step.

Second thing is related on how average reprojection error
is being calculated. It didn't take track weight into
account which could confuse users. Now average reprojection
error will give the same result as intersection/BA uses
during minimization which gives much more predictable
behavior.

Differential Revision: https://developer.blender.org/D265