IDPF/epubcheck — pull request #451 by rdeltour (2014-09-06 20:38:56+00:00)
Title: Move the rendition vocab from default to reserved

Fixes #437

* the 'rendition' prefix is still reserved and predefined
* the 'rendition' prefix is allowed to be redeclared explicitly
(with a `WARNING`)
* the Rendition vocab URI may be associated to another prefix (with a
`WARNING`)

Take the opportunity to better separate the vocabs computed for each
"class" of properties (`meta` & `scheme`, `item`, `itemref`, `link`).