Further optimisations to the Navigation building
Simplify logic in build page around checking for core/extension updates
Introduce Widget::Checkbox to automatically handle checkbox markup creation
Don't enforce the 'column' class for all Checkbox label's by default
Update to use Widget::Checkbox in the DSE/SE
Ensure anything modified in AddSectionElements delegate still works
Preserve CDATA nodes when converting XML string into XMLElement

CDATA was getting identified as DOMText and therefore sanitised when it should be preserved as a CDATA section.
Fix indentation
Merge pull request #2208 from g-wilson/integration

Preserve CDATA nodes when converting XML string into XMLElement
Move all requires to a single autoload file
Implement classmap autoloader
Move the autoload into the index instead of bundle