-frules-off

Not exactly a bug, but -frules-off doesn't do exactly what I would expect --
it effectively disables specialization, whereas it would be useful (to me,
anyway) for it to disable user-defined rules while still applying rules
generated by the compiler, such as specialization rules. Since there's
another option that disables specialization (I think), it would seem 
sensible for -frules-off to work that way. I have a fix that involves
changing activeRule (in simplify/SimplMonad.lhs) back to the way it was
before and changing lookupRule (in specialise/Rules.lhs) to check whether
opt_RulesOff is true, and, if so, only return the matching rule if it's a 
SPEC rule, but undoubtedly there's a better way.

-- 
Kirsten Chevalier * krc@xxxxxxxxxxxxxxxxxxx * Often in error, never in doubt