CC-BY-3.0: add the full text of the CC-BY 3.0 unported
-rw-r--r-- 17304 CC-BY-3.0
-rw-r--r-- 1170 CC-BY-3.0-short.md
-rw-r--r-- 6970 CC0-1.0
-rw-r--r-- 1020 CC0-1.0-short