Updated facts.py

-facts.py now includes two TMR bases. One for the current session and
one from the fact repository. Both are dicts that map name of a concept
(as a string) to a list of all instances of that concept or instances
that have that concept as an ancestor.

-Because of the new storage system, storing instances are a bit more
involved. Please use the store('instance') function.

-The load() function reads base knowledge from fact_repo.txt, which
includes documentation inside