libgnomeui 2.17.91

* Revert the single tilde patch since it didn't work
* Don't eat memory like mad when thumbnailing animated
  gifs. (Matthias Clasen)
* Updated translations:
  - Khaled Hosny (ar)
  - Josep Puigdemont i Casamajó (ca)
  - Hendrik Richter (de)
  - David Lodge (en_GB)
  - Ivar Smolin (et)
  - Robert-André Mauchin (fr)
  - Changwoo Ryu (ko)
  - Wouter Bolsterlee (nl)
  - Duarte Loreto (pt)
  - Theppitak Karoonboonyanan (th)