Remove upper bounds and close clckwrks/clckwrks#4
Remove upper bounds and close clckwrks/clckwrks#4

Also added hsx2hs, see
https://github.com/clckwrks/clckwrks/issues/4#issuecomment-246809995

judah/stackage,jonschoning/stackage,iand675/stackage,ygale/stackage,k0ral/stackage,mgajda/stackage,asr/stackage,athanclark/stackage,stackbuilders/stackage,ethercrow/stackage,lwm/stackage,clinty/stackage,phaazon/stackage,DanielG/stackage,michalkonecny/stackage,l29ah/stackage,christiaanb/stackage,wereHamster/stackage,spencerjanssen/stackage,mrkkrp/stackage,garetxe/stackage,simonmichael/stackage,GregorySchwartz/stackage,Shimuuar/stackage,massysett/stackage,int-index/stackage,soenkehahn/stackage,mstksg/stackage,peti/stackage,jaspervdj/stackage,fpco/stackage,brendanhay/stackage,Daniel-Diaz/stackage,fimad/stackage,creichert/stackage,alanz/stackage,phadej/stackage