[jhc] Multi parameter type classes

[Henning Thielemann]

Is there also anonymous access to the JHC bug+feature-tracker? I like to 
add a request for multi-type parameter classes. These are necessary to 
compile NumericPrelude, what most of my signal processing code is based 
on. I need them for instance for vector spaces in order to write frequency 
filters and interpolations that work on both mono and stereo signals. I do 
not need functional dependencies.

numericprelude$ grep -rh LANGUAGE src | sort --unique
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE NoImplicitPrelude #-}