Distinct newtypes for EnumMap.{Strict,Lazy} and Functor instances
Data.EnumMapSetWrapper: workaround for containers-0.5.0.0

∙ Now also works with base-4.5 and template-haskell-2.7.
.travis.yml: install-deps &c.
enummapset-th.cabal: bump version to 0.6.0.0

∙ Following containers' version was a silly idea.