R 3.1.1 with multithreaded support (was PR#952)

Updated given comments on https://github.com/hpcugent/easybuild-easyconfigs/pull/952

Modelled on https://github.com/hpcugent/easybuild-easyconfigs/pull/956 which added a dependency for libjpeg-turbo.

Depends on https://github.com/hpcugent/easybuild-easyconfigs/pull/1021 and https://github.com/hpcugent/easybuild-easyconfigs/pull/1020

See also https://github.com/hpcugent/easybuild-easyconfigs/pull/908

I went with the toolchains of the past since the state of new toolchains (e.g. intel-2014b) is unclear to me at this point.