WIP: more work on the docker structure, still not finished with 4_run

1_base: builds a base image, based on Ubuntu 16.10
2_buildpy: builds two images:
	2a: an image that can build Python 3.6
	2b: an image that contains the built Python 3.6 in /opt/python
3_buildwheels: builds an image to build wheel files, puts them in ../4_run
4_run: the production runtime image, which can't build anything and just runs.

docker/1_base/base.docker

@@ -2,9 +2,8 @@ FROM ubuntu:16.10
 MAINTAINER Francesco Siddi <francesco@blender.org>
 
 RUN apt-get update
-RUN apt-get -y dist-upgrade
 RUN apt-get install -qyy \
     -o APT::Install-Recommends=false -o APT::Install-Suggests=false \
-    openssl
+    openssl ca-certificates
 
-RUN mkdir -p /data/git/{pillar,config,venv,wheelhouse,python}
+RUN mkdir -p /data/git/pillar /data/config /data/venv /data/wheelhouse