Enable unAPI support in TT OPAC

Enable unAPI support in TT OPAC

We have enough information available from the context and date
plugin to construct valid unAPI IDs - so let's do it and take
one more XXX off the table. (This is good for Zotero support!)

Sadly, Zotero doesn't seem to recognize more than one unAPI
ID on the search results page; in theory it should give the
user the ability to add all of the search results at once,
but in practice it doesn't display anything.

At the same time, we can remove the duplicate unAPI placeholders
and remove unnecessary <span> elements.

Signed-off-by: Dan Scott <dan@coffeecode.net>
Signed-off-by: berick <berick@esilibrary.com>