Base Dockerfile

This begins the process of laying out the base Dockerfiles as discussed on the mailing list and within https://github.com/jupyter/colaboratory/pull/92.

I'm personally going to go with @KesterTong's outline from the colaboratory Dockerfile because I think it matches the setup we want best and is right in line with users+devs on the list.

> 1. IPython library
> 2. IPython + SciPy library (this is just the SciPy stack since IPython is part of the SciPy 1.0 stack)
> 3. IPython server
> 4. IPython + SciPy server

Dependency graph `1->2, 1->3, 2->4`

In the process here I'll be creating each of these as automated builds on the Docker Hub (albeit on the `base_images` branch).
Ah, looks like it's from IPython.

```
13:38:28 (base_images=) kyle6475@rac ~/code/docker-notebook$ ipython -c "import sys; sys.exit(1)"; echo $?
An exception has occurred, use %tb to see the full traceback.

SystemExit: 1

To exit: use 'exit', 'quit', or Ctrl-D.
0
13:38:39 (base_images=) kyle6475@rac ~/code/docker-notebook$ python -c "import sys; sys.exit(1)"; echo $?
1
13:38:45 (base_images=) kyle6475@rac ~/code/docker-notebook$ python -c "import adsfadsf"; echo $?
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: No module named adsfadsf
1
```