Updated Marketing Materials

[Allan Day <allanpday gmail com>]

Hi all,

Andreas and I have updated the sticker, badge and t-shirt designs that
are hosted on our ownCloud instance:

https://cloud.gnome.org/public.php?service=files&t=41ed7027380ff6af519cbec42498396e

The designs aren't fantastically exciting, but they are nice and are
consistent with what we have already. If anyone wants to produce
materials for conferences, I would recommend that you go here for
recommended resources.

I've also added a more prominent link to ownCloud from the Engagement wiki page.

Allan