Include page caching, action caching and sweeper modules.
Using my fork of acts-as-taggable-on for now.
Updates database schema file.

Removes uniq option from sites index, because Rails 4 does not supports it anymore.
Do not Fixes resource spec.
Fixes seeder
Using ruby gems version of rails-observers
Using my branch of acts_as_list for now.
Fixes scope syntax for Language.on_site
Explicitly require rails-observers
Fixes spec controller process syntax.
Fixes order option syntax for has_many relation in Cell.