Treat 'Last Activity' column as numeric for sorting purposes

Should have been part of #27
Automatically sort columns once data has been loaded

Since table contents are now loaded after retrieving data via XHR, it's
necessary to delay the auto-sort feature.

Fixes #29
Make manange.py aware of FORCE_SCRIPT_NAME
Properly invalidate MTIME cache
Save cached get_mtime values while refreshing stats
HACK: get the main page to show
HACK: get progress bars to show
HACK: Get progressbars to show in the main page
HACK: Fix progressbar in language pages
HACK: Fix table zebra coloring
HACK: Fix project progressbars in main page
HACK: just set item.stats to True

We now only use it in _table_row.html to determine whether the table
shows stats or not.
HACK: This tooltip is not used
HACK: Make this work after turning 'stats' into bool
HACK: Update goal code similar to

6a4c6bd66948f907666d4d1374453e1dc110e436
HACK: pass an item.code for goals

Still not working
Kill more unneeded get_stats
Fix sort key in the front page
We can do without filtering out language with 0 translations
Update project summary using AJAX