Made terms description nullable in fixtures

As they are nullable as describe in migrations https://github.com/croogo/croogo/blob/master/Plugin/Taxonomy/Config/Migration/1346931401_firstmigrationtaxonomy.php
The form input should use the configured value to tell whether it's multiple or not

Instead of hard coding it to true.
Added useful alt property for images

page_white image didnt have an alt, and thumbnails had generic default alts (thumb); this sets alt for page_white image as the mime type and the title of the attachment for thumbnails.

Signed-off-by: Rachman Chavik <rchavik@xintesa.com>
Sprinkling some __d() based on croogo/locale#21
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
Merge branch 'master' of github.com:chadrien/croogo