German language translation (de)

Lexicon files for German language
German language translation (de)

German language lexicon files (added Translation infos)
[#218] Fix property itemCls from being assigned activeCls's value
Added ability to show all childs and subchilds of selected parent album by new TV option.
snippet.gallery: add next/prev id to placeholder
album: add year field
snippet.galleryalbums: add id parameter

if set, shows only the album with the given id
gallery: allow string values for zc option
Batch import sorts by filename.
Fix getPage support in Gallery snippet
Applied GROUP BY galItem.id to prevent duplication during LEFT JOIN modx_gallery_tags
Do not cache in getList() when $sort = RAND()
Add support for selection of album cover. Can use image from gallery or upload a new one.

 - Updated version to 1.5.3-a2 for package install purporses
 - Add new field to galAlbum model - cover_filename

Signed-off-by: Egor Bolgov <egor.b@fabricasaitov.ru>
Update snippet.gallery.php

Empty galleries return an empty string. ($data)
PHP throws a fatal error "Cannot use string offset as an array".

Added a type check to break.
Added getMediaSource function - looks for setting gallery.mediaSource
Updated item+gallery to use mediasource on 'upload item'
Added Multi-upload support with media sources
Updated batchUpload to use media Source
Updated zip upload to use media source
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