- Tweaked a form validation method to prevent no type option item gets selected.
- Changed the file structure of including files.
- Tweaked the styling of the `Category` template to center the not found image.

git-svn-id: https://plugins.svn.wordpress.org/amazon-auto-links/trunk@921165 b8457f37-d9ea-0310-8a92-e5e31aec5664