Release 2.0.14

Made e-mail address optional in batch checker website interface.

This address is set with the new `BATCH_NOTIFICATION_EMAIL` config
setting and defaults to the value of `EMAIL`.

Fix counters reporting on about page

We forgot to include the description extractor in the totals. Also,
it said batch jobs were excluded from the totals, which is not the
case.

Log result id for finished batch job

Fix link in batch notification if submitted from webservice

Link to mapview examples Gist

Update Mailcheck

Use Mailcheck in the batch jobs form

This enables attachement of these handlers to elements that are
added to the DOM later as opposed to being in the original source
HTML.

Fix crash listing zero batch jobs in admin

Update OS requirement in install docs

Optional email for batch jobs from webservices

Fix default service locations

This should have been in #70

Process batch jobs grouped by email address

We previously processed batch jobs round robin, i.e., one item
for each job per round. This is fair from the job point of view,
but not from the user point of view when one user has many jobs.

We now process batch jobs one item for each user per round,
where we pick the oldest job if a user has more than one. Users
are defined by their email address.

Batch jobs submitted via the webservices all have the same email
address, so they are effectively throttled as if all from the
same user. Adapting the webservices to also allow setting an
email address is future work.