Centering the map for the clustering
Better parameters for clustering + shuffling

- The list is shuffle prior to clustering (othewise everyting is clustered
"horizontally")
- Tentative of finding some good parameters seems to work.
- Find bug into the Tester => Clement should fix it.
Matching colors for clustering, Venn.js imported

All in title
Venn update itself properly now.

There was an error in the intersection between two geoSquare. It is now
corrected, but it could be improved.

Still have to center the map.

Conflicts:
	app/controllers/Gathering.scala