fix in sparql parser bnode consistency check: apparently only applies to
INSERT DATA/DELETE DATA operations.
SES-1853 SPARQLConnection needs several tweaks to deal with the fact
that bnode id reuse across multiple updates is no longer allowed.
disabled statement serialization test since it keeps timing out when
executed as part of whole suite (strange thing is that it works fine if
executed in isolation)
Merged in ses-1853 (pull request #149)

SES-1853 fixes dealing with consequences of stricter sparql parser for update sequence with bnodes