Gallery2: Filtershow toast translations

Toast translation strings that were copy-pasted from existing "undo" and
"redo" strings. Some of these may need to be modified for the toast to
fit on the screen.

Patch Set 2: Shorten Dutch strings as per Marco Brohet's suggestion.

Change-Id: Iaa42ca57dfdd327ffde35a77e320d7f04605f682