This Exhaustive algorithm iterates through every possible pebbling configuration to determine the Pebbling Number,
but skips those configurations that contain a vertex that already has enough pebbles on it to automatically say that
the graph is solvable.
Return the result of the algorithm in the context of the problem. i.e. Solvable, Unsolvable, Unknown. This tells
more than "Done" or "Not_Done" that is given in the more general sense. This might just be "true" or "false", it
might be the encoding of a series of moves, etc.
Mostly for use in comparing results from previous versions of algorithms, and/or so we can know whether or not
data in the database is based on an older version of the algorithm. Start with "return 1.0". Go up by whatever
increments you like (e.g. 1.1, 1.2, etc. or 1, 2, 3, etc.)