Add issue template

debian, miniconda, notebook version, option updates

* Upgrade to latest debian base image
* Upgrade to Notebook 4.3
* Upgrade to Miniconda 4.2.12
* Remove USE_HTTPS env var in favor of command line options for key and cert
* Add GEN_CERT env var for generating a self-signed certificate
* Remove PASSWORD env var in favor of the new Notebook 4.3 default token auth
  or the more secure a hashed password command line option

Install Toree to conda env instead of user home

TensorFlow 0.11.0

Upgrade Spark to 2.0.2

Fixes issues with python version mismatches when using Spark

Dockerfile version for power ppc64le

adding a patch file to make Dockerfile.ppc64le more maintainable and updating the Makefile to make use of the patch file

JupyterHub 0.7

and get it from conda (conda-forge)

single-user protocol should still be compatible, so this shouldn't change supported Hub versions

Add vincent, beautifulsoup, and xlrd to scipy-notebook

Update Julia version to 0.5

This is pretty hacky -- we're using a Ubuntu 14.04 PPA to install
something on Debian Jessie -- but everything seems to work.

Add badges with image size and layers

This uses the MicroBadger badge service. It allows prospective image users to
quickly get an idea of the size of an image from glancing at the README.

Don't mix mkl and open_blas packages

* Bump numexpr to 2.6 so it comes from conda-forge
* Install nomkl