happy: update to version 1.19.4
haskell-defaults.nix: simplify references to the latest version of happy
happy: remove obsolete versions 1.18.8, 1.18.11, 1.19.2, and 1.19.3
haskell-gtk2hs-buildtools: update to version 0.13.0.0
haskell-haskell-token-utils: update to version 0.0.0.3
haskell-hjsmin: update to version 0.1.4.7
haskell-hoogle: update to version 4.2.34
haskell-hspec-expectations: update to version 0.6.0
haskell-hspec: update to version 1.10.0.1
haskell-lens: update to version 4.3
haskell-mono-traversable: update to version 0.6.0.4
haskell-path-pieces: update to version 0.1.4
haskell-pipes-aeson: update to version 0.4.1.1
haskell-pipes-group: update to version 1.0.1
haskell-pipes-zlib: update to version 0.4.0.1
haskell-postgresql-simple: update to version 0.4.3.0
haskell-safe: update to version 0.3.6
haskell-streaming-commons: update to version 0.1.3.1
haskell-th-desugar: update to version 1.4.2
haskell-thyme: update to version 0.3.5.2