Dutch translation
Merge pull request #316 from zenphoto/Dutch-translation-Dev

Dutch translation
force caching of image processor URIs detected in metadata (fix #310)

Since apparently the consumers of this metadata are not willing to
accept image processor URIs as images, this change will "fetch" the
image when the page loads. This will not help the first reference, but
subsequent references will find the images cached/
no direct link to zp-core/index.php
some small code cleanup
add Horizontal rules