XSB Src (SVN)-old

Working on better memory management for incremental tabling. One
of the incremental tabling structures, hashkeys, was not being
deallocated when a key is removed from a hashtable, in
hashtable1_remove(). Although each key is just 8 bytes or so,
this function is called every time we recompute a table, so not
freeing the space adds up.

To fix this, I had to dive into hashtable.c, and put a call to
smdeallocate() in hashtable1_remove() -- it looks like for some
reason it was never there.

It seems likely that there are more memory leaks corresponding to
hashtables and their keys -- I'll keep looking.

somehow the previously committed version was old (missing psc_find)

Fixed bug in module inferencing in load_dyn, catching an inconsistency
due to bad ordering of declaration and use.

uncommented CURRENT_MODULE

fixed a bug that was confusing gpp

Fix a bug in new dynamic loading in handling export statements, and
to give an error in a case of wrong order of export/use that introduced an
inconsistency.

/dll flag needs to be /DLL on some MSVC compilers.

Mostly updated information about statistics/0, which had gotten out of date.

Made load_dyn and load_dync load modules correctly as the compiler
(with minor caveats).
Added psc_find.

Added builtin psc_find to find a psc record without adding it if it's not there.
Made a getc safer for general character codes (noticed when checking
windows problem.)