Added containerTpl (with navigation placeholders) and totalVar Placeholder

containerTpl has the following navigation placeholders:
nav.first, nav.prev, nav.current, nav.next, nav.last

Snippet could work with getPage now (but it is not changing the current gallery together with getPage).
Update snippet.galleryalbums.php
Update snippet.galleryalbums.php

Bugfix and count placeholder
Update snippet.galleryalbums.php

Bugfix for no current album
[GalleryAlbums] Added containerTpl (with navigation placeholders) and totalVar placeholder