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/3_buildwheels/build.docker

@@ -0,0 +1,15 @@
+FROM pillar_py:3.6
+MAINTAINER Sybren A. Stüvel <sybren@blender.studio>
+
+RUN apt-get install -qy \
+    git \
+    build-essential \
+    checkinstall \
+    libffi-dev \
+    libssl-dev
+
+ENV WHEELHOUSE=/data/wheelhouse
+ENV PIP_WHEEL_DIR=/data/wheelhouse
+ENV PIP_FIND_LINKS=/data/wheelhouse
+
+VOLUME /data/wheelhouse

docker/3_buildwheels/build.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+
+# macOS does not support readlink -f, so we use greadlink instead
+if [ $(uname) == 'Darwin' ]; then
+    command -v greadlink 2>/dev/null 2>&1 || { echo >&2 "Install greadlink using brew."; exit 1; }
+    readlink='greadlink'
+else
+    readlink='readlink'
+fi
+
+TOPDEVDIR="$($readlink -f ../../..)"
+echo "Top-level development dir is $TOPDEVDIR"
+
+WHEELHOUSE="$($readlink -f ../4_run/wheelhouse)"
+if [ -z "$WHEELHOUSE" ]; then
+    echo "Error, ../4_run might not exist." >&2
+    exit 2
+fi
+
+echo "Wheelhouse is $WHEELHOUSE"
+mkdir -p "$WHEELHOUSE"
+
+#docker build -t pillar_wheelbuilder -f build.docker .
+
+GID=$(id --group)
+docker run --rm -i \
+    -v "$WHEELHOUSE:/data/wheelhouse" \
+    -v "$TOPDEVDIR:/data/topdev" \
+    pillar_wheelbuilder <<EOT
+set -e
+# Build wheels for all dependencies.
+cd /data/topdev/blender-cloud
+# pip3 install wheel
+# pip3 wheel --wheel-dir=/data/wheelhouse -r requirements.txt
+# chown -R $UID:$GID /data/wheelhouse
+
+# Install the dependencies so that we can get a full freeze.
+pip3 install --no-index --find-links=/data/wheelhouse -r requirements.txt
+pip3 freeze | grep -v '^-[ef] ' > /data/wheelhouse/requirements.txt
+EOT
+
+# Remove our own projects, they shouldn't be installed as wheel (for now).
+rm -f $WHEELHOUSE/{attract,flamenco,pillar,pillarsdk}*.whl