address issues in The Battle of Megiddo book

[fredzannarbor]

1. Abstracts should be relevance sorted
2. tl;dr should be deactivated until implemented
3. some articles don't have abstracts, some are too long -- detect/summarize/truncate
4. Abstracts should perhaps be labeled as "Algorithmically Identified Abstracts"
5. spider external links for additional content
6. detect/warn content that is difficult to disambiguate from search intent (e.g. there were multiple battles of Megiddo)
7. user-provided content needs editing
8. add User-contributed needs (c) notice
9. add Front matter, back matter, and algorithmic metadata © 2016 PageKicker.