Bug 6594: Schema.org structured data for OPAC display

To support schema.org processors, such as Google, Bing, and Yandex,
structure our data so that it has machine-readable attributes. This pass
declares the CreativeWork sub-types as well as Product for the main
bibliographic record details, and uses the Offer type for holdings
information per the W3C Schema Bib Extend community group discussions.

Signed-off-by: Dan Scott <dan@coffeecode.net>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Comments on final patch.
Bug 6594: Move subject keywords schema.org markup into <span> element

Google's rich snippets tool gets confused by the <a property="keywords">
approach, so stuff another span inside the <a> element to remove
confusion with the href attribute.

Signed-off-by: Dan Scott <dan@coffeecode.net>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Bug 6594: Correct schema.org context for item status

We were inserting the <link> element inside an open <td> element, which
HTML parsers, even the most forgiving, do not like very much.

Signed-off-by: Dan Scott <dan@coffeecode.net>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>