Fix: Link.class does not get autopopulated

Due to jquery.slug.js uses the `class` attribute to identify
input tag to populate.
Fix: Don't assume builtin plugins are always active
Configure AttachmentsController for Wysiwyg

This was previously configured in Ckeditor plugin which is the wrong
place to do it.
Removing hardcoded references to FileManager
Fix: getimagesize still triggers a warning for missing files
chooser_title added to choser
Deprecate ImageHelper::$cacheDir
Don't configure other plugin's setting

Related:
- croogo/croogo@543ccc2
- croogo/Ckeditor@154c5fd4
Updating submodules

- croogo/locale@6154982958d903a
- croogo/Ckeditor@154c5fd430b
- CakeDC/migrations@7724ccd5
- CakeDC/search@9bcaa6fe045
Updating AUTHORS.txt for release 1.5.5
Updating VERSION.txt for release 1.5.5
Specify Plugin for behavior

When removing plugin bootstraps, this caused a Behavior not found error.
Fixed tests - refs #220
Set all Routing.prefixes to false in menus linking

So menus links don't keep current route in generated URL
Block weird image types from trying to imagecreatefrom*

i found an errror when i uploaded a favicon because it was trying to execute the function imagecreatefrom* with the mime type: image/vnd.microsoft.icon. So we set an array of valid suffixes and check against it.
Fix translated model caches not being flushed after saving translation.
Merge branch 'pr/220'
Merge branch 'pr/224'
Fix: Don't lose event data in saveNode()
Upgrade submodule to croogo/Ckeditor@e88496ac0ea83