Speed up and despam CLI startup

[rec]

Description

Tiny annoyance removed.

Starting up the superduperdb cli with e.g. python -m superduperdb --help took three seconds and generated six lines of irrelevant output.

These two tiny changes reduced it to 0.3 seconds and no output.

[nenb]

Question for my education: What's the rationale for moving the imports inside the functions?

[rec]

@nenb: Good question, it turns out to be a useful technique.

If the import is at the top of the file, then it happens immediately when the file is loaded, including any side effects like loading large libraries that different things.

If the import is in code, it happens the first time you execute that code, and then never again.

All else being equal, imports should be at the top of the file, so if there's a problem it gets detected early as possible, but "not wanting to import some large and irrelevant module" is a perfectly good reason to perform local imports. :-)