[Fixes #656] Multiple Attachments widget

* Upload Attachment now opens a modal dialog.
* Show attachments in properly styled table.
* Constraint attachment thumbnails size in preview table.
* Add Delete button for each row.
* Show message if there are no attachments.
* Delete attachment no longer uses deprecated link_to_function from delete (deprecated)
* Preview image opens a new tab (allows New blocks to continue safely)
* Removed custom 'loading' image (should have a CMS wide consistent one if needed)
* Add Never Mind button for modal.
* Fixed Jquery missing errors for inline page editing.

Catalog Updates:

* Catalog - Slug is now correctly based of the name field.