* 3.1.3

* added Colin as contributor

* Changes to wheezy

- Added wheezy as a FROM
- Update source list
- Added autotools-dev and automake for building littler
- Used Dockerfile from 3.1.0 for sys deps
- Install littler from tarball

* littler version via ARG

This was forgotten in the previous commit, where only the non-devel images
where tested.

All the rocker r-base/r-apt based images already have the R recommended
packages pre-installed, see e.g. [0].

By installing the recommended packages also on the r-ver based images the
compatibility with packrat is improved, when it is used in a mixed mode
on top of different distribution with recommended packages pre-installed
and r-ver based images. Packrat does not include recommended packages in
its package library packrat.lock, if those are in the system library,
see also the pakrat docu page 5 in [1]. This leads to unresolved
dependencies and would require manually adding those also to the packrat
library.

The R installer already includes a mechanism to also install the
recommended packages, which is just activated by this change. The R
recommended packages are also versioned by the R version, see [2]-[6].

[0] r-recommended: https://github.com/rocker-org/rocker/blob/master/r-base/Dockerfile#L50
[1] https://cran.r-project.org/web/packages/packrat/packrat.pdf
[2] https://cran.r-project.org/src/contrib/${R-Version}/Recommended/
[3] https://cran.r-project.org/src/contrib/3.5.1/Recommended/
[4] R_PKGS_RECOMMENDED: https://github.com/wch/r-source/blob/trunk/share/make/vars.mk
[5] https://github.com/wch/r-source/blob/trunk/src/library/Recommended/Makefile.in
[6] https://github.com/wch/r-source/blob/trunk/tools/rsync-recommended

remove explicit openblas in R installation, replaced it by the shared Blas system, as used by the debian R package. it is now possible to switch Blas implementation using LD_LIBRARY_PATH or update-alternatives by example. Also added the --with-tcltk flag, that was already automatically setup to make it more explicit.

will see if this results in cache files that inflate image size signifcantly...