simplify replace method
temporarily elide 2.5/6 issues
The HTML5Lib warning mechanism for import was not complete (the 'true' value for the flag wasn't set)
Per latest decisions in the RDFa Working Group, have added a warning triple when a prefix, either defined in the ancestor or in the initial context, is redefined.
merge
deprecated node.md5_term_hash
Made Literal.language/datatype into readonly properties.
fixes #226
added a leading space before ; for repeat predicate/object pairs in turtle serializer
Added dc11 to the initial context's prefixes, per DCMI's request (although the official change would not happen until early 2013…)
Merge branch 'master' of https://github.com/RDFLib/rdflib
Ensure that orig_source is always bound in structureddata parser
Merge branch 'master' of https://github.com/RDFLib/rdflib
Extend guard to protect from None.
Merge branch 'master' of github.com:RDFLib/rdflib
Elide slot/classvar conflict in Python 3.3
Changed the media type for json-ld (although this is not used as part of this parser, the code is identical to the one used by a general service, so better synchronize this)
Merge branch 'master' of https://github.com/RDFLib/rdflib
Updated the microdata registry to the ones in the W3C mercurial repo
doc update for Graph.label and mention Graph.preferredLabel

Graph.label docs didn't point out that it might return any label and
Graph.preferredLabel wasn't mentioned in the graph intro to resolve the
above problem.
Merge pull request #242 from joernhees/master

doc update for Graph.label and mentioning Graph.preferredLabel