Added additional default prefixes from the RDFa 1.1 initial context http://www.w3.org/2011/rdfa-context/rdfa-1.1
Added additional default prefixes from the RDFa 1.1 initial context
http://www.w3.org/2011/rdfa-context/rdfa-1.1

bsampaio/PHP-SemanticWeb-20142,bsampaio/PHP-SemanticWeb-20142,bsampaio/PHP-SemanticWeb-20142