XSB Src (SVN)-old

Fix minor problem with read error handling when term contained a "string",
in which case it would fail without a message, when atom_codes failed on
the structure.

Modified slightly when to force string_gc, so that instead of forcing
string GC whenevery the string space expands 4-fold, to do it only if
the assert space isn't also expanding. Was finding that for large loads,
unnecessary string GC's were taking half the load time...

Fixed bug in printing warning message, when module is usermod, since
now psc_data may be a string.

airplane hacking -- making the executable table directive behave the
same as the compiler declaration.

airplane hacking. adjusted error handling so that, among other
things, the compiler doesn't go into an infinite loop when you type

table p/1 as X.

Airplane work... Documented table preds as options.

Adding these (note done before).

Adding this for constraint_tests.

... and another one ...

Forgot to commit the extern statements for Varenumerator_trail_top.