Sesame 2.7.0-beta2 updates

Update to Sesame-2.7.0-beta2, including the new RDFFormat.RDFA constant and the new ParserConfig/ParserSetting code.

NOTE: I had to disable the fetching of tests in RdfaParserTest or the rdfa1.1/html5/0278.html test would have failed the build, even though it was removed recently from the repository. The autofetching was switched on again in the same commit where the test file was removed, so the test kept coming back for me. I did not commit the change to RdfaParserTest in this Pull Request.