Implement IDA* search for puzzles

[barrybecker4]

See
https://en.wikipedia.org/wiki/Iterative_deepening_A*

Since it is a depth-first search algorithm, its memory usage is lower than in A*, but unlike ordinary iterative deepening search, it concentrates on exploring the most promising nodes and thus does not go to the same depth everywhere in the search tree. Unlike A*, IDA* does not utilize dynamic programming and therefore often ends up exploring the same nodes many times.