Suggestion: add a functional interface

[erelsgl]

Thanks for the great library! I suggest to allow a fuctional interface. That is, instead of creating a class for each problem, allow to pass the functions neighbors, is_final etc. as direct arguments to the solver. This may be simpler for some users.

[jrialland]

Hello, thx for your remark. In fact this function already exists (its name is "find_path", and its usage is demonstrated in https://github.com/jrialland/python-astar/blob/master/tests/basic/test_basic.py