Implement automated benchmarking

[wingos80]

Implement benchmarking functionality to run solvers on the standard benchmark tests.

[wingos80]

added some dictionaries and print statements for this in commit f2438ec

Still need to add:

• pickling the BENCHMARK_results dictionary
• local storing benchmark results in human readable format (as .csv perhaps)
• automatically run benchmark over all the 15 decided (so far) benchmark cases

[wingos80]

Add 3BV scoring for benchmarking too.

[wingos80]

Decided the benchmark cases to be simply the default minesweeper difficulty levels.

Added pickling, local storing, and automatically run over all 3 benchmark cases with commit 02245df

Use this website to find useful scores/statistics to compile for the benchmark.

[wingos80]

Opening new issue on adding scores to benchmark, closing this one as complete.