fix bug #521 in TopNMetricBuilder class
untested code for computing the precision and recall of a recommender output.
untested code for computing the independent recall of a recommender
untested code for computing the independent recall of a recommender  (rest of code from last commit)
Create aggregate JaCoCo report
Refactor CI post-build scripts
Drop last remaining use of Index/Indexer (closes #443)
Use mvn --batch-mode
Fix lenskit-predict descriptions
Write the lenskit(1) man page (#507)
Write lenskit-version man page (#507)
Write lenskit-graph manual page (#507)
Write train-model man page (#507)
Write the pack-ratings man page (#507)
Write predict and recommend man pages (#507)
Write eval man page (#507)
Render man pages for binary packages (#507)

- Filter man pages to make them saner
- Render them in the packaging flow
LensKit CLI documentation indexes (#507)
Install Pandoc in Travis for man pages (#507)
Travis build tweaks & cleanups