Move GEM_PATH part of rubygems' setup hook to ruby

Fixes #1413

Signed-off-by: Shea Levy <shea@shealevy.com>
Upgrade cppunit to 1.13.2
haskell-RSA: update to version 2.0
haskell-crypto-pubkey: update to version 0.2.4
haskell-digestive-functors-heist: update to version 0.8.4.0
haskell-fast-logger: update to version 2.0.3
haskell-fclabels: update to version 2.0.1
haskell-lens: update to version 3.10.1
haskell-wai-extra: update to version 2.0.1.1
haskell-wai-logger: update to version 2.0.2
haskell-yesod-static: update to version 1.2.2.1
build-support/cabal: recognize the "this package indirectly depends on
multiple versions of the same package" warning from Cabal and abort the
build if it occurs.
pkgs/build-support/cabal: clean up the code that sets rpath for shared executables
pkgs/build-support/cabal: add 'buildTarget' attribute to allow passing flags to "./Setup build"
haskell-prettyclass: add version 1.0.0.0
haskell-cipher-aes128: add version 0.5
haskell-DRBG: add version 0.5.1
haskell-defaults.nix: cabal2nix now requires Cabal 1.16.x or later
pkgs/build-support/cabal: the configure-phase warning check can be
disabled by setting 'strictConfigurePhase' to 'false'

This is necessary for some packages, like dns, because cabal warns about
multiple versions of the same dependency being used, but the usage is fine,
actually, so we want the build to succeed. Packages that depend on 'doctest'
also have this issue <https://github.com/sol/doctest-haskell/issues/69>.
pkgs/top-level/release.nix: build the ghc 7.2.2 binary