Improved verse segmentation

[benjaminking]

This PR adds new features to the verse segmentation script and refactors it for better organization. New features include:

• Greedy selection of verse breaks (instead of in-order)
• A new alignment method that uses Fast Align to filter out erroneous Eflomal word alignment pairs
• Preliminary splitting of passages into smaller sub-passages for better word alignments
• Saving of sub-passages and their alignments
• Improved heuristics for correcting close, but not quite correct verse breaks

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This change is 

[TaperChipmunk32]

@TaperChipmunk32 partially reviewed 3 files and all commit messages, and made 1 comment.
Reviewable status: 3 of 17 files reviewed, all discussions resolved (waiting on Enkidu93).