ASCII Maze Master

A recursion-based maze solver for challenge 165/intermediate.
Changed path deque to stack

Changed the data structure holding the maze path from a deque to a
stack.

Instead of pushing a node on entry and popping when it’s determined to
not be part of the path, now push only when a node is known to be part
of the path. (This reduces the number of nodes created.)
Mazemaster refactoring

Prints error messages instead of throwing exceptions. Added sample maze.
Merge branch '165-intermediate'