Charm icon guidelines, feedback wanted

[Jorge O. Castro]

When Rick H asked for charm icon guidelines we kind of cowboy agreed
to do icon.svg at the root of the charm.

I submitted this as a revision to the Charm Policy but was rejected
due to lack of detail, so I asked the design team who's doing the work
on the GUI/jujucharms.com to basically tell us how to do icons, and
here's the result:

- https://docs.google.com/document/d/1hBTH_7RLUYMV-VhZOGxb-bFHICXyVRU4t8L79Dlea80/pub

We are still missing some things, like I know Clint wanted and
explicit guideline for filesize, etc but I figure this is a good start
to building that. It's currently on google docs but I plan on
resubmitting it as part of the core documentation.

Also apologies to Patrick Hetu, who submitted an icon for Django
literally 20 minutes before I got these guidelines.

Thoughts/opinions?

--
Jorge Castro
Canonical Ltd.
http://juju.ubuntu.com