Add pluralization of demo and default quantity units

localization/de.php

@@ -224,11 +224,17 @@ return array(
 	'Tinned food cupboard' => 'Konservenschrank',
 	'Fridge' => 'Kühlschrank',
 	'Piece' => 'Stück',
+	'Pieces' => 'Stücke',
 	'Pack' => 'Packung',
+	'Packs' => 'Packungen',
 	'Glass' => 'Glas',
+	'Glasses' => 'Gläser',
 	'Tin' => 'Dose',
+	'Tins' => 'Dosen',
 	'Can' => 'Becher',
+	'Cans' => 'Becher',
 	'Bunch' => 'Bund',
+	'Bunches' => 'Bunde',
 	'Gummy bears' => 'Gummibärchen',
 	'Crisps' => 'Chips',
 	'Eggs' => 'Eier',