Revert "implemented functionality to manage the cache and to reduce the number of useless cached configurations"

This reverts commit fa24ad8ddb2be469f0751e881fcb8b5eec8f6d2e.
Revert "added a small helper function to identify an empty mask; i.e., a mask that masks no square"

This reverts commit 1de6f3f907dea50e32a2587229dbdbd142a828ad.