[gnome-user-docs] Created tag 3.15.91

[Ekaterina Gerasimova <kat src gnome org>]

The signed tag '3.15.91' was created.

Tagger: Ekaterina Gerasimova <kittykat3756 gmail com>
Date: Mon Mar 2 23:25:03 2015 +0000

    Version 3.15.91

Changes since the last tag '3.15.90':

Daniel Mustieles (3):
      Updated Spanish translation
      Updated Spanish translation
      Updated Spanish translation

Dimitris Spingos (1):
      Updated Greek translation

Ekaterina Gerasimova (4):
      Update screenshots for 3.16
      Update shell-introduction for message tray
      Add comment to shell-notification
      Version 3.15.91

Jim Campbell (2):
      validation: Fixed date formatting to resolve validation error.
      Updated files-delete.page for new 3.16 delete behavior