XSB Src (SVN)-old

Now allowing maximum functors to be 2**16 - 1. Various changes
to make this work properly for pure SLG execution. Much of this
simply involved changing the occurrences of byte types in
psc-oriented routines to int. While I was at it, I changed the
name from the confusing insert() to insert_psc().

No attempt was made to expand bytecode, so large arity terms are
not available for explicit compilation. Also, I dodn't fiddle
around with assert/retract. However, nearly all Prolog builtins
have been checked to ensure they work with large-arity terms, as
have been interned tries. I started working on checking tabling,
although there are more features to check.

For good luck, I also increased the HEAP_GC_MARGIN.

Fixed is_most_general_term to work with large terms (lists as well as functors)