Updated Czech translation
Marked images in help as untranslatable

Marked icon on index.page and images on bonustiles.page as untranslatable.

https://bugzilla.gnome.org/show_bug.cgi?id=725253
Updated Czech translation
Mark most images/videos as not translatable, as they contain no translatable strings.

https://bugzilla.gnome.org/show_bug.cgi?id=725368
Updated Spanish translation
Updated Galician translations
Prepare 3.11.91
Updated Traditional Chinese translation(Hong Kong and Taiwan)