Add DeriveDataTypeable, fix build on ghc 7.6
Add DeriveDataTypeable, fix build on ghc 7.6
frontrowed/wai,utdemir/wai,sordina/wai,utdemir/wai,yesodweb/wai,utdemir/wai,creichert/wai,creichert/wai,sordina/wai,frontrowed/wai,erikd/wai,utdemir/wai,erikd/wai,tolysz/wai,sordina/wai,tolysz/wai,frontrowed/wai,tolysz/wai,kazu-yamamoto/wai,sordina/wai,erikd/wai,tolysz/wai,yesodweb/wai,erikd/wai,frontrowed/wai,kazu-yamamoto/wai