Re-wrote questing

Depending on the trigger type (%look, %drop), there may or may not be
trigger values to be stored. Look has none, while drop has one (name of
the dropped item to look for), for example.
Depending on the function type (%dialogue, %awardexp) there may or may
not be function values. %dialogue requires 3 lines of values (the
dialogue and two reference names) while %awardexp has 1 (the numerical
amount awarded).

The React function knows how to access trigger values, while the other
Reaction functions know how to access function values.