Add license text and COPYING suggestions

This content should be independent of both the boot camp development model (branches vs repos) and the content model (Markdown vs ReST), so I think it's safe to push now.  This sort of thing may take a few revisions to get right, and we want to have it in place before the real work gets started.

I'm working up a Signed-off-by proposal, but it's currently blocking on a clearer [provenance for the kernel DCO][DCO].

[DCO]: http://article.gmane.org/gmane.linux.kernel/1400065