Reopen #2537 and re-instate some tests and haddocks
Reopen #2537 and re-instate some tests and haddocks

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