Make visited optional for unvisited-neighbors
Use hash-map for all-walls-without-doors
Make visited optional for reachable-neighbors
Make visited optional for all-locations-visited?
Save outer walls for 2-by-2 so we can use in tests
Do not limit unvisited-neighbors by size of maze
Test that all-walls returns outer maze walls
Test all-walls-without-doors returns outer walls
Don't bounds check for reachable-neighbors
Add add-walls-on-perimeter
Use all-walls-on-permimeter in tests
Remove border around maze

We are now generating walls out there.
Remove size param from all-walls-for-location
Generate maze starting with walls around perimeter
Move test for generate-maze next to solve-maze
Pass new-maze directly to solve-maze
Add test for permimeter of a maze of size 3
Simplify all-walls-on-perimeter
Rename all-walls-on-perimeter to outer-walls
Add fill-in-missing-walls for making inner walls