Add / adjust copyright headers on all files.

• Python files already have appropriate AGPL header, except need adjustment to provide exception for HTML (maybe also CSS for the sake of clarity?) files. See: http://www.gnu.org/licenses/gpl-faq.html#WMS though we will probably need to make some adjustments to that.
• HTML templates should contain CC0 header. See: http://wiki.creativecommons.org/CC0_FAQ#May_I_apply_CC0_to_computer_software.3F_If_so.2C_is_there_a_recommended_implementation.3F
• Move COPYING to AGPLv3.txt
• Download CC0_1.0.txt:http://creativecommons.org/publicdomain/zero/1.0/legalcode.txt
• Create a new COPYING which describes that python code is under AGPLv3 (AGPLv3.txt) w/ exception for HTML templates, Javascript under AGPLv3 w/ exception for HTML, and HTML templates / images / CSS of base theme all under CC0 (CC0_1.0.txt)

If we end up having CSS files by the time this is written we should also add headers to these, but do this in the style listed at the bottom of this post: https://creativecommons.org/weblog/entry/27094

Since we're using the stylesheet from diveintohtml5 and the web site looks a lot like the diveintohtml5 site, we should add a line to the bottom of our website pages along these lines:

"site design inspired by diveintohtml5"

with "diveintohtml5" a link to the diveintohtml5 site.

This should probably get done (or alleviated by a different site design) before we launch on the 30th.

StatusNet has both good writeup of legalcode descriptions of external libraries: https://gitorious.org/statusnet/mainline/blobs/master/README#line90

And also has a good policy for external libraries: https://gitorious.org/statusnet/mainline/blobs/master/extlib/README

Evan has made clear that it's cool (even a good idea) for us to just copy that extlib/README file and adapt it to mediagoblin, and that's what we should do.

We should also find a nice directory to keep these all in, and just use symlinks to move them around to appropriate places (eg, bootstrap.py from zc.buildout can be symlinked to the toplevel of the package, jquery can be symlinked to the mediagoblin static app media directory).