Json maps as pairlists

pair lists have the advantage that the order of labels is not sorted. 
I tried to create compact (and still readable) output. Maybe longer output is fine, too.
Because I was not sure if brackets still match I wrote a parser and tested that the .json output for the basic libraries can be parsed and printed again with the same result. 

I've also looked into http://hackage.haskell.org/package/json