Fixes menubar scss mixins and adds new icon.
Removes unused ferret search lib.
Adds a complete callback for Alchemy windows.

The complete callback gets called after the window loaded its content.
Removes background image preloader jquery plugin.

It wasn't in use anyway.
Prevent default link event on element window's toolbar buttons.

Fixes an issue with Turbolinks always reloading the page while clicking on the element window's toolbar buttons.
Fixes Turbolinks issues with link overlay.
Removes unnecessary clipboard select helper and fixes select box css class.
Use stable compass-rails

compass-rails 1.1.x works with Rails 4 and 2.0.alpha.0 has been janked

See: https://github.com/Compass/compass-rails/commit/2c54193cdda7b152135a908c9481dca83f32045d
Merge pull request #434 from ahx/use-compass-rails-stable

Use stable compass-rails
Set I18n.enforce_available_locales = true
Removes `render_essence_editor_by_type` helper.
Refactors admin/elements_helper_spec
Removes unused helper `contents_form_field_ids_string`
Set `I18n.enforce_available_locales = false` in test env.
Removes `page_selector` helper method.

This is a ugly, hard to test, proxy helper, with no value at all.
We have `pages_for_select` helper that does everything we want.
Converts `admin/essences_helper` hash syntax.
Adds missing specs to `admin/essences_helper`
Adds ActiveRecord based DummyUser model to Dummy app.

So we can test activerecord related feature on the user class (e.g. userstamp)
Adds specs for several lib files.
Do not raise if Rails is not 4.0.0

Bundler already handles this kind of stuff.