XSB Src (SVN)-old

Changed bit declarations from unsigned int to byte (unsigned char).
This is more space efficient, but was really done because there is
some issue with MSVC when the unsigned int is used. There must be some
alignment and/or displacement kind of problem with the unsigned int.
I don't have the time/energy/interest to try to track down the exact
reason....sorry.

Fixed typo so that bit-fields carved out of a byte will again add up to 8.

changed documenting comment for crypto_hash

Updated for pos/neg edges and added more test cases.

Support for positive and negative edges in SDG analysis.

Added bit indicating negative call to subgoal frame -- supports SDG analysis. Extended get_sdg_info to handle both positive and negative dependencies, along with non-incremental tables.

Updated documentation for SDG analysis of incomplete subgoals

Added missing export of attribute_portray_hook/3.
(Found by Miguel's "tool".)

Updated documentation for SDG predicates.

Added tests for sdg-oriented predicates.