Feature Requests: God's Number Search, pause/restart and use less memory

[DougCube]

Two parts to this...

I run out of memory on a 128GB machine with -M 98304 (96GB). It would be good if instead of crashing when it runs out of memory, to switch to writing parts out to disk. Perhaps hash the internal data structure into chunks and put each chunk into a different file.

Related to this is the ability to pause and restart, perhaps just from finishing a depth or at a finer granularity somehow. And this would be achieved by ofc writting the internal state to disk and reading it back on restart.