Collision solver fails against DungeonRooms and imperfect mazes

[john-science]

All of the maze solvers in mazelib are supposed to work with imperfect mazes. But I recently found that the Collision solver fails against DungeonRooms and imperfect mazes (with loops).

This goes counter to our documentation:

mazelib/docs/MAZE_SOLVE_ALGOS.md

Line 5 in 053aefb

Because users are allowed to create and modify mazes in such a great variety of way, the `mazelib` library will only support universal maze-solving algorithms. That is, `mazelib` will not implement any maze-solving algorithm that can't, for instance, solve imperfect mazes (those with loops or more than one solution). Otherwise, the user will have to know internal details about the maze generating / soliving algorithms they use, and if they are compatible.

So, I think we have two options:

1. Improve our Collision solver, to match the documentation.
2. Just remove this solver; though that is API-breaking.