Merge branch 'refs/heads/2.7-stable'

Conflicts:
	Gemfile
	app/assets/javascripts/alchemy/alchemy.dragndrop.js.coffee
	app/assets/javascripts/alchemy/alchemy.initializer.js.coffee
	app/assets/javascripts/alchemy/alchemy.tinymce.js.coffee.erb
	app/assets/stylesheets/alchemy/menubar.css.scss
	app/controllers/alchemy/admin/pages_controller.rb
	app/controllers/alchemy/pages_controller.rb
	app/models/alchemy/element.rb
	app/models/alchemy/page.rb
	app/models/alchemy/page/elements.rb
	app/models/alchemy/page/scopes.rb
	app/models/alchemy/page/users.rb
	app/models/alchemy/picture.rb
	app/models/alchemy/user.rb
	app/views/alchemy/admin/contents/create.js.erb
	app/views/alchemy/admin/dashboard/index.html.erb
	app/views/alchemy/admin/elements/_refresh_editor.js.erb
	app/views/alchemy/admin/elements/create.js.erb
	app/views/alchemy/admin/elements/fold.js.erb
	app/views/alchemy/admin/languages/_form.html.erb
	app/views/alchemy/admin/pages/edit.html.erb
	app/views/alchemy/admin/pages/info.html.erb
	app/views/alchemy/base/permission_denied.js.erb
	app/views/alchemy/base/redirect.js.erb
	app/views/alchemy/essences/_essence_richtext_editor.html.erb
	lib/alchemy/modules.rb
	lib/alchemy/version.rb
	spec/controllers/admin/pages_controller_spec.rb
	spec/controllers/admin/pictures_controller_spec.rb
	spec/helpers/admin/contents_helper_spec.rb
	spec/models/content_spec.rb
	spec/models/element_spec.rb
	spec/models/page_spec.rb
Do not use action caching for pages#show anymore.

We now use fragment caching  on the pages#show template and send etag and cache-control headers.
Adds cache_digests support.
Add to_partial_path to models.
Uses Rails 4-0-stable branch
CacheDigests support for cells and essences.
Adds template_tracker specs.
Cache all essence views and adds specs
Use content as local variable in essence views again.

We cannot use the partial name, this causes a lot of problems with existing helpers and specs.
Refactors admin/contents_helper
Fixes errors attachments controllers and template tracker specs
Fixes essence view specs.
Changes how the pages controller gets the layout to render.

No more class method, instead the layout_for_page method gets called in render call.
Fix cells factory name attribute.
Refactors the render_elements helper.
Refactors render_element helper.
Use render_page_layout in pages#show, to have the standard layout fallback working.
Adds spec for attachment#restricted?
Adds a temporary fix to suppress phantomjs warning on os x mavericks.
Adds specs for page model.