XSB Src (SVN)-old

Eliminated recursion in xsb_eval (evaluating expressions is/2) by using an explicit stack. Now no bound on expression depth.

Change to doc of not_exists.

Small changes to Section 5.5 (Tabling for Termination)

Added current module to warning about redefining clauses, as the clauses are not redefined everywhere.

Fix a minor with add_to_db. Docs.

Restore Makefile which was inadvertantly changed.

changed xwams due to addition of bldkavars intstruction.

Add compiler optimization to combine consecutive bldavar insts to new bldkavars.

Add new instruction bldkavars (similar to unikavars) for efficiency. Will shortly commit compiler and .xwam changes.

Fix read error when operator is followed by a semicolon, so should be read as atom.