SES-2065 added a simple lexer for SPARQL query prologs. The lexer
assumes the query is syntactically correct to keep it lightweight and
returns a list of tokens for prolog items, with the last item being the
'rest of the query'.
SES-2065 added a few unit tests.
SES-2065 added second method to lexer that more efficiently consumes the
prolog and returns only the last (REST_OF_QUERY) token. Added some
constants per review feedback.
SES-2065 added null check
SES-2065 added multiline comment matching regex to lexer. seems to make
no real perf diff.
Merged in SES-2065-sparql-comments (pull request #291)

SES-2065 added a simple lexer for SPARQL query prologs.
set version to 2.7.12
fix in update parser to deal with negative syntax test case.
Revert "fix in update parser to deal with negative syntax test case."

This reverts commit e6b299b89ae72497479e40cc2758d17de60ba674.
fix in named graph parsing for insert/delete data.