Remove collections package to support Python 2.6
General stats for the global site.
Fix Leaderboard link in community page.
Updated about page to include Global Stats page
Cache the page view
Most active apps and users in last 24 hours added
Template to show the global stats
Fix hours stats zero fill.
Merge pull request #416 from PyBossa/issue-stats

Issue stats
Merge commit '1b29' into culttag-redux