Merge pull request #118 from Prillan/expensive-event-bug

Expensive event bug.
Merge remote-tracking branch 'upstream/master' into sql-optimizations
Added ranks to player infobox.
Merge pull request #117 from Prillan/country-rank

Added ranks to player infobox.
Added 5 min caching to /results/

See issue #120.
Merge remote-tracking branch 'upstream/master'
Use prefetch_related on /results/

Well, should have known that... Fixes #120.

Decreased the time on 2014-01-05 from 6s to 0.3s.
Admin interface for Period

Allows admins to manually trigger a recompute of Periods from the
admin page.
Trigger recompute on Match change.

The corresponding Period will now be recomputed when a Match is
changed in the admin interface. Includes deletion of matches.
Trigger recompute if Match is deleted from the list.
Merge pull request #121 from Prillan/admin-interface

Admin interface improvements.