[tei-council] Implementation of @selector on <rendition>

At the FtF I got the go-ahead to implement the feature request described in detail here: http://wiki.tei-c.org/index.php/Proposal_for_@selector_attribute_on_renditio... with the proviso that I should once more call it to everyone's attention for any final objections before I go ahead and do it. If I don't hear objections in the next few days I'll make this change. Cheers, Martin