Light Movement Initialization

Added a list in each Scraper that keeps track of the order in which it
visits its children. Given the tree, rooted at 1:

1
+-----+
|     |
2     3
+-+-+ +
| | | |
4 5 6 7

The visitation path will be 1,2,4,2,5,2,6,2,1,3,7,3,1

Once it's fully traversed, it'll just visit all of its parents until it gets back to
the root. This will, most likely, need refining in the coming days.
Working prototype

Lights move, but slam into walls. No Plan B. Needs fixes.