Hotfix/fix license

I pulled together a joint work license to merge the original CfA MIT license with our public domain/CC0 license. This is based heavily on how CFPB has handled this same kind of release.

This seems like it should work to me, but I'd particularly like to get opinions from @rjmajma and @konklone.

Also, note I branched this from/am contributing it to the master branch. If we're good with these fixes, we should probably cherry pick the commits into dev as well.