icon for social bookmarks based on software-update-available.svg from the tango
project, available under:
git://anongit.freedesktop.org/git/tango/tango-icon-theme.git

modification: johannes raggam <raggam-nl@adm.at>
original authors:
Lapo Calamandrei <calamandrei@gmail.com>
Rodney Dawes  <dobey.pwns@gmail.com>
Jakub Steiner <jimmac@gmail.com>

