Fixed settings issue.

The following warning was shown when I clicked on links:
'GLib-GIO-Message: Using the 'memory' GSettings backend. Your settings will not be saved or shared with other applications.'
Update `macvim` package to v7.4.355

MacVim's maintenance has stagnated, so this moves `macvim` to a new maintainer.
Additionally, the `-headerpad_max_install_names` linker flag is passed to
prevent problems when setting the rpaths.
dwb: add wrapper and use GTK2 for plugin support
Removed CRAN mirror that was incorrectly handling 404 errors, causing
builder to abort.
Added CRAN archive to R package derivation to prevent R expressions from
breaking when any package is updated.
Introduced haskellPackages.HPDF
pythonPackages.beets: 1.0.0 -> 1.3.6
Merge pull request #3131 from bennofs/dwb-wrapper

add dwb-wrapper for plugin support
Fix info command

The "info" command has been broken on NixOS since
457fdb38425fd00378f213f9bd5c306ed99395bf (proving that nobody uses
info).
Merge pull request #3208 from jbedo/master

Fix R expressions when packages are updated
haskell-RSA: update to version 2.0.0
haskell-haskell-token-utils: add version 0.0.0.2
haskell-regex-tdfa-rc: add version 1.1.8.3
haskell-parsers: update to version 0.11.0.3
haskell-vty: update to version 5.1.1
haskell-bloomfilter: update to version 2.0.0.0
haskell-crypto-conduit: update to version 0.5.4
haskell-esqueleto: update to version 1.4.1.3
haskell-libmpd: update to version 0.8.0.5
haskell-pipes-binary: update to version 0.4.0.2