Maze Solver Exercise

Note for developers:You have 2 global objects available:

- maze: represents a Maze object with the following functions:
    - move(direction): Moves the player in the given dir
        ('up','down','right','left')
    - explore(direction): Returns information about the NEXT cell
        in the given dir ('up','down','right','left'):
        0: Wall
        1: Passage, not yet visited
        2: Entry
        3: Exit: You have to find that one
        9: Passage, already visited
    - isExit(): Returns true if the player is on the
        exit cell at the moment


- solver: The Maze Solver object, to be implemented by a smart guy :-)