Docker: reproduce cmake issue with python 3 on 16.04

docker/hpp-fcl/source.Dockerfile

+FROM ubuntu:16.04
+
+ARG EIGENPY_VERSION=2.4.3
+ADD https://github.com/stack-of-tasks/eigenpy/releases/download/v${EIGENPY_VERSION}/eigenpy-${EIGENPY_VERSION}.tar.gz /
+ARG HPP_FCL_VERSION=1.4.6
+ADD https://github.com/humanoid-path-planner/hpp-fcl/releases/download/v${HPP_FCL_VERSION}/hpp-fcl-${HPP_FCL_VERSION}.tar.gz /
+
+RUN apt-get update -qqy \
+ && apt-get install -qqy \
+    build-essential \
+    cmake \
+    libassimp-dev \
+    libboost-all-dev \
+    libeigen3-dev \
+    liboctomap-dev \
+    libpython3-dev \
+    python3-numpy \
+ && rm -rf /var/lib/apt/lists/*
+
+RUN tar xvf /eigenpy-${EIGENPY_VERSION}.tar.gz \
+ && tar xvf /hpp-fcl-${HPP_FCL_VERSION}.tar.gz
+
+WORKDIR /eigenpy-${EIGENPY_VERSION}/build
+
+RUN cmake -DPYTHON_EXECUTABLE=/usr/bin/python3 .. \
+ && make -sj4 \
+ && make test \
+ && make install
+
+WORKDIR /hpp-fcl-${HPP_FCL_VERSION}/build
+
+# TODO: doesn't work.
+# ref https://github.com/jrl-umi3218/jrl-cmakemodules/issues/422
+#RUN cmake -DPYTHON_EXECUTABLE=/usr/bin/python3 .. \
+ #&& make -sj4 \
+ #&& make test \
+ #&& make install