* Move common DB handling code to a superclass used by all db objects
* Create a super class for all the Opp/Var/Num calsses that does the
  typechecking on all the methods and maby some default actions.
* Make pri and oppdb global vars
* Remove the InitDB methods
* Remove the {'Type'} vars and use ->isa instead
* Add typechecking to all methods
* Work on the docs


