Make working with dependencies more sane
use constant for jquery version

also include jquery with top priority in preview
more sane LinkUtil::link

• You can now pass a language to LinkUtil::link without presupposing that it will be amended to the path (there’s now a separate parameter for that)
• The second parameter defaults to null which means the Manager will be asked whether or not to include the language in the link.
• Passing true or false as the languge still works and behaves as if null was used for the language and true/false for the Gretchenfrage