send2trash not work

https://github.com/jupyter/notebook/issues/3130
Now, files not delete on https://hub.docker.com/r/jupyter/base-notebook/ and derived container images.

Update scipy-notebook packages

Update tensorflow to 1.5, keras to 2.1

Added missing conda clean to pyspark-notebook Dockerfile

Update miniconda installer to 4.4

Update scikit libraries

Release notes can be found here https://github.com/scikit-image/scikit-image/blob/master/doc/release/release_0.13.rst

Release notes can be found here http://scikit-learn.org/stable/whats_new.html#version-0-19-1

Update toree to rc5

Update jupyterlab and extensions

Update jupyterlab from 0.31 to 0.32.

Update the following extensions to matching versions:
- jupyterlab/hub-extension
- jupyter-widget/jupyterlab-manager
- jupyterlab_bokeh

Force npm cache clean

Remove facets directory

The `cd` command switches to the user's home directory (away from the directory we want to delete)
Then we remove the facets directory using the full path

In start.sh ensure usename jovyan exists before attempting usermod

Keyserver pool

Remove tornado<5 pin

Need to install as NB_UID, not root, to keep all /opt/conda
folders writeable by the default user

update all-spark to toree 0.2.0rc4

Keyserver used in Hashicorps Nomad files

Run additional scripts in /usr/local/bin/start-notebook.d/

Drop the `r` channel

Use conda-forge's blas package w/openblas

As conda-forge does not use the `nomkl` package, but instead uses the
`blas` package to select BLAS versions, install the `blas` package and
select the `openblas` implementation.

The `r` channel has been considered part of `defaults` since `conda` version `4.3.0`. So it should already be taken into consideration by `conda` installs without having to explicitly add the channel. Further the `conda-forge` channel has incorporated an ever growing, healthy stack of R packages. As such it appears all of the R packages used in this stack now come from `conda-forge` and not `defaults`. Given all of this, it seems safe to drop the `r` channel from explicit addition to the channel list.

hkp://pool.sks-keyservers.net over keyserver.ubuntu.com see
https://sks-keyservers.net/overview-of-pools.php

ReadTheDocs site, User Guide sections