Updated YUI to 3.18.1
Fix EZP-23670: Install YUI3 via bower
EZP-23670: use YUI3 installed with bower in the unit tests
EZP-23670: make the unit tests in coverage mode are running
EZP-23708: Added a basic field view to display the XmlText fields
EZP-23708: Added a basic field edit view for XmlText fields
Simplified a selector in the edit/textblock.css
Small refactoring in TextBlockEditView
EZP-23670: Fixed the newly added unit tests