Include all lightbox2-helper-images as data:

Include the 4 images next.png, prev.png, loading.gif and close.png into the respective files.

- Except for loading.gif this hardly increases file-sizes
- Decreases the amount of http-requests+related delays
- Never again any button is missing because of wireless-fuck-ups or 404s.
- Makes it even easier to include lightbox as you don't have to edit any configuration or use absolut paths if you use lightbox from different directories/sub-domains
- Easier upgrades! You can keep the lightbox-directory as-is and just copy it to /lightbox on you server