desired effect: tile clicked is the only tile that rotates, no children of tile should rotate
along with parent transform.
this is challenging because it is a parent child relationship.
the method attempted here is to break the children from the parent while the parent is rotating, then reattach the children to the parent when done. because of the existing code requiring a reference to
children to remove them from the scene if the user moves the mouse away, provisions had to be made to prevent undefined references.
Merge branch 'child-tiles-no-rotation' of https://github.com/dervishxgit/uninav into child-tiles-no-rotation

Conflicts:
	uninav.js