Stats pages

This pull request adds the Stats pages:

Global:
/stats/global

Regional
/stats/regional/[:iso]

Country
/stats/country/[:iso]

Adds 3 controllers (one for each stat type) in the /app/controllers/stats foder.

It also creates an integration test and controllers tests for the features above.

Still work to do on CSS and and the views may be refactored.

Geospatial stats are not available so they are commented in the controllers and not present in the views
Yeah, I was planning doing that in the beginning, but then I realized that I was doing again the unit tests. But you are right. One thing is testing the results and another thing is testing if they are being shown.