Solve the Maze

The solve() method on the Maze class simply calls the _solve_r method starting at i=0 and j=0. It should return True if the maze was solved, False otherwise. This is the same return value as _solve_r.

I wrote a depth-first solution to the maze, feel free to do something different if you want. Here were my steps.

The _solve_r method returns True if the current cell is an end cell, OR if it leads to the end cell. It returns False if the current cell is a loser cell.

1. Call the _animate method.
2. Mark the current cell as visited
3. If you are at the "end" cell (the goal) then return True.
4. For each direction:
   1. If there is a cell in that direction, there is no wall blocking you, and that cell hasn't been visited:
      1. Draw a move between the current cell and that cell
      2. Call _solve_r recursively to move to that cell. If that cell returns True, then just return True and don't worry about the other directions.
      3. Otherwise, draw an "undo" move between the current cell and the next cell
5. If none of the directions worked out, return False.

Call maze.solve() in the main function and watch your algorithm do its work!