Cli improvements

Some simple CLI improvements:

• allow saving to multiple files simultaneously
• fix interactive shell

closes #53 (closed)

The pipeline failure is because master still requires ipython even though the need for it is eliminated in this MR. It will not be an issue after this is merged.

changed the description

added 7 commits

• 1fe8af94...b69d4267 - 4 commits from branch gwinc:master
• 6c7123de - cli: allow specifying multiple save files
• 1544b114 - cli: improve some help strings
• 626b6ff0 - cli: fix interactive mode

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added 1 commit

• a5c15ed8 - cli: fix interactive mode

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mentioned in commit 0891d76b

merged