Various recent changes and bug fixes

Added docviewer (XHTML only)
Added docheadviewer (XHML only)
Added Document properties viewer & editor
Added Document Context
Allowed semantic results, entity facts widgets, and simple word query
in searchbar widget to contribute structured search criteria to a
content search context (joint queries fed by search and semantics)
Changed one column page to fix layout issues with bootstrap-roxy.css
Added bootstrap CSS support
Reworked CSS to be consistent between widgets
Added saveProperties, getProperties to mljs core (JSON only)
Added rest client tests
Added ontology information
Rebuilt build downloads
Updated rdb2rdf widget styles, layout, bug fixes