The best links connects a linking object and its text occurrence, e.g. the link to documentation is near documentation's occurrence in the text. Since no explicit link to the guide the guide text font became bold but link to the docs moved to doc's text occurence

Print image size after building it

Updating Power PC LE Dockerfile

Fix #1077

Use pip --no-cache-dir to install tensorflow

Add a recipe for auto_sklearn

Updating miniconda version to 4.8.2

Changed the regular expression in start.sh that reads the /etc/sudoer…

Regular update 2020 W18

Matplotlib tests + helpers methods

* Documentation `common.md` updated
* `test_nb_user_change` test written

Dependencies resolution fails with numba `0.49`. I do not know the root cause.
Here is the difference between the two versions.

```bash
$ conda search --info numba

numba 0.48.0 py38hb3f55d8_0
---------------------------
file name   : numba-0.48.0-py38hb3f55d8_0.tar.bz2
name        : numba
version     : 0.48.0
build       : py38hb3f55d8_0
build number: 0
size        : 3.4 MB
license     : BSD 2-clause
subdir      : linux-64
url         : https://conda.anaconda.org/conda-forge/linux-64/numba-0.48.0-py38hb3f55d8_0.tar.bz2
md5         : 580c5132d9f575462db40daf20201ff1
timestamp   : 2020-01-27 17:39:57 UTC
constraints :
  - tbb >=2018.0.5
  - python_abi * *_cp38
dependencies:
  - libgcc-ng >=7.3.0
  - libstdcxx-ng >=7.3.0
  - llvmlite >=0.31.0,<0.32.0a0
  - numpy >=1.14.6,<2.0a0
  - python >=3.8,<3.9.0a0
  - setuptools

numba 0.49.0 py36h0573a6f_0
---------------------------
file name   : numba-0.49.0-py36h0573a6f_0.conda
name        : numba
version     : 0.49.0
build       : py36h0573a6f_0
build number: 0
size        : 3.1 MB
license     : BSD 2-clause
subdir      : linux-64
url         : https://repo.anaconda.com/pkgs/main/linux-64/numba-0.49.0-py36h0573a6f_0.conda
md5         : cdbf81e0d643b5e90441ccf110b97a3d
timestamp   : 2020-04-17 17:08:20 UTC
constraints :
  - tbb >=2018.0.5
dependencies:
  - libgcc-ng >=7.3.0
  - libstdcxx-ng >=7.3.0
  - llvmlite >=0.32.0
  - llvmlite >=0.32.0,<0.33.0a0
  - numpy >=1.14.6,<2.0a0
  - python >=3.6,<3.7.0a0
  - setuptools
  - tbb >=2020.0
 ```

* Bump `base-notebook`
	* OS version
	* `jupyterlab`
* Bump `scipy-notebook`
	* `beautifulsoup4`
	* `cloudpickle`
	* `dask`
	* `numba`
	* `xlrd`: version specified (it was not the case)
* Bump `datascience-notebook`
	* `r-devtools`
	* `r-forecast`
	* Julia version
	* Test added to check if Julia is correctly installed (`julia --version`)
	* Note: A new version of `r-base` is out `4.0.0` however it cannot be installed yet since dependencies with other packages cannot be resolved.
* Bump `r-notebook`
	* Same as `datascience-notebook` except Julia.
* Bump `all-spark-notebook`
	* `r-sparklyr`

* Maplotlib is an important package. It has now its own test checking that a plot can be generated and exported has an image.
* Some helpers methods added to the `Makefile` mainly permitting to clean containers and images
* Improved assertion messages of some tests

ihaskell-notebook binder urlpath

Change the Community Stacks ihaskell-notebook Binder urlpath to the revived IHaskell.ipynb notebook.