Trying to eliminate the minimum 10m distance for replacing the original
junction vertex - this is a small threshold. When _not_ replacing this
vertex, the unzorro code will wreck havok on a traffic circle.
(If there is no suitable vertex to use, it will snap to a point between
the nearest vertices, see #4146)
* Support move, rotate, reflect, delete post paste on multiselection
* Improve text and error msgs for singular vs multi selections
* Move `disabled` checks from actions to operations
* Reproject center of rotation (closes#3667)
* Cleanup tests