Minimal hits objects (no aggregates) from transaction-old
Lib code to load redirector hits tsv files
Add rake task for redirector TSVs

Also requires changing to SQL-based db:schema:load, otherwise
InnoDB is used for hits and hits_staging. myISAM is much
quicker since we currently have no need for transactions /
contention there
Avoid a mound of unwanted AUTO_INCREMENT values

(in db/structure.sql)
Merge pull request #21 from alphagov/greatest-hits

Bring back hits and a way of loading them