americano & vendor libraries updates

Hi all,

here are a few updates of the coffee templates. It follows the pull request on the cozy-template full js.
On server side (needed, or the template does not work anymore) :
* update americano version from 0.2.10 to 0.3.5
* update americano-cozy version from 0.1.4 to 0.2.5

On client side : 
* add console helper (it was in js version)
* update jquery version from 1.9.1 to 2.1.1
* update underscorejs version from 1.4.4 to 1.6.0
* update backbonejs version from 1.0.0 to 1.1.2
* add backbone mediator (it was in js version)
* add full version of bootstrap 3.1.1
* removed normalize.css as it's part of bootstrap
* renamed the "scripts" folder of the "vendor" folder to "javascripts" so it's the same name as in the "public" folder
* renamed the "styles" folder of the "vendor" folder to "stylesheets" so it's the same name as in the "public" folder
* added css for bootstrap
* added bootstrap fonts in a new folder "assets" in the "vendor" folder

I still have a message requiring underscore.map, i was lazy to check were it comes from.