Parser has a new idea of expressions; planner fix

Parser has a new idea of expressions; planner fix

 - Move handling of the ','/2 and whenever/2 operators into the ANF
   processor, next to '*'/1, '&'/1, and is/2, rather than the parser.
 - Remove the side-condition field in rule forms
 - Fallout from this exposed a really, really bad initialization bug
   in the rule planner, which is now hopefully corrected.