XSB Src (SVN)-old

Fixed multithreaded calls to throw_permission_error that I just added.
Thanks, Barry.

Forgot to include this in previous commit.

Added some error checking for read/write errors to throw more
instructive permission errors in case of errors. Much more to be
done, but this is a (small) start. This is becoming more important as
XSB, Inc. runs large, long-running programs over sometimes flakey
networks, and we need to be told if/when the network goes down.

Added missing export for get_interpreter_index/1.

Updated section on timed_call to include timed_call_modify and current_timed_call.

Minor changes. Changed get_timed_call_index to get_interpreter_index, and
also use this for abort/1.

Implemented timed_call_modify, and current_timed_call.

Added utility predicate to tables to print out tabled predicates with number
of calls and answers. Makes it easier to track down tables that should
have been abolished but aren't.
In writing it descovered a minor bug in predicate_property that I also fixed.

Refactored slightly to provide new slightly lower-level interface to this
functionality.

Added definitions for get_mod_for_psc, and get_mod_name.