release data as it's used during addRound rather than waiting until the end

[kathleenleeper]

when adding a round, it would be nice to preload and release data as each round is warped and added-- purely from a Lustre drive management perspective.

[kathleenleeper]

Alternatively it should be async/independent of the nextflow run? -- e.g. I currently run the preload and offload separately so that e.g. the displacement field and the preloading compare directly in a loop shaped like this:

~/move_data.sh preload $1 &
nextflow $script $1 -c $process_settings
~/move_data.sh release $1 &

This would also get around the bug currently for #19 which e.g. causes problems when trying to run addRound for multiple rounds in a row overnight (I mean...also fixable by passing in "don't release the data" but)