add an option to save RAM in the large calculation

[BenjaminDbb]

In many times, we need MPI to do massive calculations, therefore, there are LARGE result in the resultlist, leading to the memory leak. I add an option to disable record the resultlist.

[adrn]

Thanks - this seems like a good idea! I added some suggestions based on renaming the argument.

[coveralls]

Coverage decreased (-0.1%) to 60.046% when pulling 4c2006c on BenjaminDbb:BenjaminDbb-save-RAM into 8f3f520 on adrn:main.