interpolate problems on level 0 mesh with parent-child nodes

[millerta]

Interpolate appears to break on background mesh with parent-child nodes see /home/agable/lagrit/tickets/interp_parent,IO,new,,2.0,defect,major,Aaron Gable,2010-07-12
The interpolate function appears to break when given a background mesh with parent-child node relationships.
An example is contained in /home/agable/lagrit/tickets/interp_parent/
Notice that it gets - quite clearly - the wrong answer. A node lying almost directly on the surface, but not part of the original surface itself, is given a distance in the thousands, when it should be near zero.
Run: cmo / select mesh resetpts / parents rmpoint / compress resetpts / itp cmo / DELATT / mesh / -dist- compute / distance_field / mesh / surf / -dist-
It now gets the right answer.