SES-1882 test case and fix for isolation problem in in-memory store.
SES-2031 : Initial import of LuceneSail with FluidOps patch
SES-2031 : Link from sesame-sail to lucene
SES-1882 : Remove unused imports accidentally added
SES-1882 simplified by taking out unnecessary check on active lock
SES-2028 fix for concurrency issue in Native Store. Only change is that
we check if the transaction lock has been acquired by this Connection -
if not we only read committed triples.
SES-2025 better handling in case of uncommitted results in another
connection. cleaned up tests.
SES-2028 logic and name of transactionLockActive method now in sync.
SES-1882 SES-2028 SES-2025 disabled isolation tests for HTTP
connections.
SES-1039 handleClose and run method now acquire explicit lock when
using/dereferencing the parserThread object.
SES-1039 handleClose and run method now acquire explicit lock when
using/dereferencing the parserThread object.
Merge branch 'ses-1039' of ssh://bitbucket.org/openrdf/sesame into
ses-1039

Conflicts:
	core/http/client/src/main/java/org/openrdf/http/client/BackgroundTupleResult.java
SES-1039 undo of unintended commit
SES-1990 SPARQL parser now dumps INSERT DATA/DELETE DATA data block as
raw string, parsing is left to dedicated parser (subtype of TriG parser)
as part of SailUpdateExecutor.
SES-1990 fixed handling of named graph/context in case of removal
SES-1990 various fixes to make compliance tests greenline.
SES-1990 fixes in negative syntax parser tests
SES-1990 minor cleanup in grammar
SES-1990 minor cleanup in javadoc, added override annotation.
Clean up potential NullPointerExceptions.

In cases where a value has been checked for null-ness but then
used, prefer an explicit exception to an inevitable NPE.