key_lock_solver
A solver for Stephan Baumegger's Key Lock puzzle
The class AStarSolver uses A* search to remove pieces one by one and solve the puzzle.
The solve(_) method starts from a given state and completes the solution until all pieces are removed
The reset(_) method starts from a given state and gives the steps required to return the puzzle to the original 'fresh-out-of-the-box' state.