Needed to show links to next/prev albums

In my page I need the possibility to show a link to the next/prev album of the currently shown album.
For this I added two placeholder properties to the gallery snippet:
prev: contains the id of the previous album
next: contains the id of the next album

In order to show only the link to one album, I added the parameter 'id' to the galleryAlbum snipped,
which will specify the id of the album to show.