R: update to version 3.1.1
nixos/jekins: add services.jenkins.extraGroups option

This makes it easy to give jenkins extra privileges by adding group
memberships. Use with care :-)
sbt: drop unconditionally set $SBT_OPTS variable from script

... and rename simple-build-tool to just "sbt", which is the name
everybody uses these days.
haskell-arbtt: update to version 0.8.1.4
haskell-Chart-cairo: update to version 1.3.1
haskell-Chart-diagrams: update to version 1.3.1
haskell-Chart-gtk: update to version 1.3.1
haskell-Chart: update to version 1.3.1
haskell-DAV: update to version 1.0.2
haskell-aeson-qq: update to version 0.7.3
haskell-attoparsec: update to version 0.12.1.1
haskell-base-prelude: update to version 0.1.4
haskell-blaze-builder: update to version 0.3.3.3
haskell-boundingboxes: update to version 0.2
haskell-case-insensitive: update to version 1.2.0.0
haskell-checkers: update to version 0.4.1
haskell-criterion: update to version 1.0.1.0
haskell-cuda: update to version 0.6.5.0
haskell-diagrams-cairo: update to version 1.2.0.2
haskell-diagrams-lib: update to version 1.2.0.3