Extended DB schema for scoring

Terms stores (Score, Consensus, Class) and new table TermStats
keeps all the information needed for maintaining term scores.
Class and consensus information now displayed in UI. Next, update
score on reputatation change and on vote change.
added TODOs for tomorrow
Combined Terms and TermStats
sea --score-terms

Compute scores of the terms in the database. This will be useful
for verifying consistency.
Merge branch 'scoring' of https://github.com/cjpatton/seaice into scoring
Basic scoring

Check consistency on startup, use preScore()/postScore() on casting
or changing a vote. The next step will be to do this in constant
time. Also, prevent reloading when starting flask.
Changed contribute to add, examples
search bar on every page
Import/export bug fixes

Import Comments and Tracking, properly format timestamps, unique
constraint on (Tracking.user_id, Tracking.term_id), rollback when
breaking unique constraint.