Scoped out the necessary directory structure.

Registering a new team would fail on a fresh clone because the fs module
does not support recursively creating directories.
Added support for Redis 2.8 (and dropped support for Redis 2.6).

Refer to redis.io/commands/ttl for more information.

Starting with Redis 2.8 the return value in case of error changed:
  * The command returns -2 if the key does not exist.
  * The command returns -1 if the key exists but has no associated
    expire.
Classified attempts on submission dashboard.

Based on whether the timer has expired and whether any successful
attempts have been made.

Also allow for older graphs (i.e. those for which new submissions are
no longer accepted) to continue to be downloaded.
Fixed issue where no error messages flashed on failed submit.

Changed to store flash contents in `res.locals`, instead of
`app.locals`.
Added descriptions (key) for color-coded submission statuses.
Fixed issued with popover from upgrade to Bootstrap 3.

The content option no longer overrides the data attribute. Renamed the
attribute from `content` to `teams-list`.
Made separate results table for each category group.
Made result tables into an accordian component.

Can click on the heading to expand the group and see the results.