[jhc] applicative vs. special-functors

[Henning Thielemann]

It seems that special-functors and applicative serves a similar purpose, namely 
providing Applicative, Foldable and friends for base-1.0. But they are not 
exactly the same, since applicative contains Control.Arrow, too. Thus I have to 
extend all packages that use Applicative by a Cabal switch that include 
applicative instead of special-functors for JHC. Hm.