Repa family
Repa family

Between LTS-6 and the latest nightlies, `repa` was removed. The maintainer of the repa-* packages doesn't use stackage, but has given me permission to add them back. They build successfully with `nightly-2016-09-01`.
massysett/stackage,fpco/stackage,judah/stackage,phadej/stackage,DanielG/stackage,jonschoning/stackage,brendanhay/stackage,ethercrow/stackage,wereHamster/stackage,asr/stackage,garetxe/stackage,k0ral/stackage,l29ah/stackage,spencerjanssen/stackage,creichert/stackage,lwm/stackage,Daniel-Diaz/stackage,mstksg/stackage,int-index/stackage,stackbuilders/stackage,simonmichael/stackage,christiaanb/stackage,Shimuuar/stackage,iand675/stackage,fimad/stackage,phaazon/stackage,mgajda/stackage,ygale/stackage,jaspervdj/stackage,mrkkrp/stackage,michalkonecny/stackage,alanz/stackage,peti/stackage,clinty/stackage,GregorySchwartz/stackage,soenkehahn/stackage,athanclark/stackage