Implement minor alignment spacing improvements

[dchiller]

Fixes #30.

Before

After

Fixes #32.

Previously, we would infer an additional barline even in the case where all sections of volpiano and text had the same number of words. Now, we don't infer any additional barlines in this case, but simply add extra empty sections or extra sections of barlines to the end of either the text or volpiano (as we already did in the case where the text and volpiano had the same number of barlines).

Also, adds the dependency lock file that I had previously neglected to commit.

[jacobdgm]

This looks good. Leaving a couple of comments on purely cosmetic things, which you're totally fine to not address.