Update our custom Bootstrap to 2.3.1

Rebase customizations on Bootstrap 2.3.1, update Bootswatch Cosmo to 2.3.1
and Font Awesome to 3.1.1.
Update LESS to 1.3.3
Tweak variant lookup forms
Update handlebars to 1.0.0-rc.4
Refactor rights in templates
Manage API tokens