meter improvements

- can unwrench meters now without needing to unwrench the pipe beneath
- AIs and ghosts can still click to examine
- other mobs don't read meter instead of doing whatever it is they are clicking for, e.g. shooting a gun
- 3 tile range check for non-AI/ghost still in place
- added feedback when no power or broken
leftover from the old code, makes little difference, but you are right it looks weird.