This adds the possibility for the HTML parser to gather typed items URLs
annotated in HTML tags with itemscope and itemtype attributes (see
microdata specification https://www.w3.org/TR/microdata/ ), notably
Types from the schema.org vocabulary, but also Types/Classes from any
other vocabulary, such as the common ones listed in the RDFa core
context ( https://www.w3.org/2011/rdfa-context/rdfa-1.1.html ).
When a crawl is started, a new field to exclude content from scraping is
available. The field can be identified with the class name of div tags.
All text contained in such a div tag where the configured class name(s)
match are not indexed, while the remaining page is indexed.
Thus enable getpageinfo_p API to return something in a reasonable amount
of time on resources over MegaBytes size range.
Support added first with the generic XML parser, for other formats
regular crawler limits apply as usual.
For faster processing (measured about 2 times faster on many real-world
examples) and more advanced detection (previous algorithm detected only
URLs separated from the rest of the text by a space character).
add "datetime" property of <time> tag to scrapers startdate list.
Datetime is parsed as iso8601 (xml) date, html5 allows partial as well
as duration (not handled by this)
luccioman