A more useful Monoid instance for Data.Map

[John Wiegley]

> -1 on breaking the existing Monoid instance.  I'd prefer either:
>
> a) A newtype for the additional Monoid instance, or
> b) providing an associative operator equivalent to the new Monoid instance

-1 on breaking the existing instance from me too, with a +1 for Gabriel's
proposed fix.

-- 
John Wiegley
FP Complete                         Haskell tools, training and consulting
http://fpcomplete.com               johnw on #haskell/irc.freenode.net