XSB Src (SVN)-old

Flags are now copied into threads

Working version of the multi threaded engine - available for knowledge of developers only

added tests

took care of egcc, kgcc and friends

Extended index/2 to work for assert-type indexing by giving a 0
hash-table size, which is interpreted by index/3 as default size.

Change added to delete_return so that negation-failure simplification
is properly performed.

Test added for combining delete_returns and simplification.

Release cursor after an SQL statement that has no result set.

Fix a coercion to avoid an MSVC warning.

Altered the manner in which the truth of negated subsumptive
predicates are evaluated. Originally I relied upon the interpretive
timestamp-based relevant-answer collection function, but this requires
the Time Stamp Indices to be present in the TST. If the producer has
completed before the collection, then these structures would have
already been be reclaimed.

The new approach checks for a relevant answer using the
trie_get_return/2 builtin. If one is found, then the literal can be
failed. Otherwise, the producer must be checked for completion and
whether the negative-delay flag has been set. This is performed
through a new builtin, lrd_success/2. Therefore, slg_not/1 is restored
for handling variant tabled predicates only.