add server cron for preening stale accounts
use +new Date on cron
user.setNull for lastCron right away, to avoid missing lastCrons
remove console.log on undefined lastCron (still gotta figure out what
to do with them)
add remove_dummy_acounts migration
Merge branch 'master' into preen-users
cleanup cron
include cron on server load
two weeks should be long enough, rather than 1mo.
don't delete on invalid cron, but undefined cron. still thinking on this
Merge branch 'master' into preen-users
another attempt at cron set optimizations
taskObj tweaks
Merge branch 'master' into preen-users

Conflicts:
	src/app/index.coffee
	src/app/scoring.coffee