Add mar18c and cleaner multistage build process

Dockerfile

 FROM debian:stretch
 ARG release
 ENV release=${release}
-RUN apt-get -y update && apt-get install -y libx11-6 libpng16-16 libfftw3-3 libcfitsio5 libforms2 python python-numpy python3 python3 libgtk2.0 curl
-RUN echo 'export GAG_ROOT_DIR=/gildas-exe-$release' >> /etc/bash.bashrc && echo 'export GAG_EXEC_SYSTEM=x86_64-debian9-gfortran' >> /etc/bash.bashrc && echo 'source $GAG_ROOT_DIR/etc/bash_profile' >> /etc/bash.bashrc
-COPY gildas-exe-$release.tar.gz /
-RUN tar xvzf gildas-exe-$release.tar.gz
+RUN apt-get -y update && apt-get install -y \
+    libx11-6 \
+    libpng16-16 \
+    libfftw3-3 \
+    libcfitsio5 \
+    libforms2 \
+    python \
+    python-numpy \
+    python3 \
+    python3-numpy \
+    libgtk2.0
+RUN echo 'export GAG_ROOT_DIR=/gildas-exe-$release' >> /etc/bash.bashrc && \
+    echo 'export GAG_EXEC_SYSTEM=x86_64-debian9-gfortran' >> /etc/bash.bashrc && \
+    echo 'source $GAG_ROOT_DIR/etc/bash_profile' >> /etc/bash.bashrc
+COPY gildas-exe-$release .
+# COPY gildas-exe-$release.tar.gz /
+# RUN tar xvzf gildas-exe-$release.tar.gz

Dockerfile.dev

 FROM debian:stretch
 ARG release
 ENV release=${release}
-RUN apt-get -y update && apt-get install -y libx11-dev libpng-dev libfftw3-dev libcfitsio-dev libforms-dev python-dev python-numpy python3-dev python3-numpy libgtk2.0-dev gfortran curl
-RUN curl http://www.iram.fr/~gildas/dist/gildas-src-$release.tar.gz | tar xz
-RUN bash -c "cd gildas-src-$release && GAG_SEARCH_PATH=/usr/lib/x86_64-linux-gnu source admin/gildas-env.sh && make && make install"
-RUN echo 'export GAG_ROOT_DIR=/gildas-exe-$release' >> /etc/bash.bashrc && echo 'export GAG_EXEC_SYSTEM=x86_64-debian9-gfortran' >> /etc/bash.bashrc && echo 'source $GAG_ROOT_DIR/etc/bash_profile' >> /etc/bash.bashrc
-RUN rm -Rf gildas-src-$release
-RUN cd gildas-exe-$release && curl http://www.iram.fr/~gildas/dist/gildas-doc-$release.tar.gz | tar xz
+RUN apt-get -y update && apt-get install -y \
+    libx11-dev \
+    libpng-dev \
+    libfftw3-dev \
+    libcfitsio-dev \
+    libforms-dev \
+    python-dev \
+    python-numpy \
+    python3-dev \
+    python3-numpy \
+    libgtk2.0-dev \
+    gfortran \
+    curl
+RUN curl http://www.iram.fr/~gildas/dist/gildas-src-$release.tar.gz | tar xz && \
+    bash -c "cd gildas-src-$release && GAG_SEARCH_PATH=/usr/lib/x86_64-linux-gnu source admin/gildas-env.sh && make && make -j 4 install" && \
+    echo 'export GAG_ROOT_DIR=/gildas-exe-$release' >> /etc/bash.bashrc && echo 'export GAG_EXEC_SYSTEM=x86_64-debian9-gfortran' >> /etc/bash.bashrc && echo 'source $GAG_ROOT_DIR/etc/bash_profile' >> /etc/bash.bashrc && \
+    rm -Rf gildas-src-$release && \
+    cd gildas-exe-$release && curl http://www.iram.fr/~gildas/dist/gildas-doc-$release.tar.gz | tar xz

Dockerfile.multistage

+FROM debian:stretch as builder
+ARG release
+ENV release=${release}
+RUN apt-get -y update && apt-get install -y \
+    libx11-dev \
+    libpng-dev \
+    libfftw3-dev \
+    libcfitsio-dev \
+    libforms-dev \
+    python-dev \
+    python-numpy \
+    python3-dev \
+    python3-numpy \
+    libgtk2.0-dev \
+    gfortran \
+    curl
+RUN curl http://www.iram.fr/~gildas/dist/gildas-src-$release.tar.gz | tar xz && \
+    bash -c "cd gildas-src-$release && GAG_SEARCH_PATH=/usr/lib/x86_64-linux-gnu source admin/gildas-env.sh && make && make -j 4 install" && \
+    echo 'export GAG_ROOT_DIR=/gildas-exe-$release' >> /etc/bash.bashrc && echo 'export GAG_EXEC_SYSTEM=x86_64-debian9-gfortran' >> /etc/bash.bashrc && echo 'source $GAG_ROOT_DIR/etc/bash_profile' >> /etc/bash.bashrc && \
+    rm -Rf gildas-src-$release && \
+    cd gildas-exe-$release && curl http://www.iram.fr/~gildas/dist/gildas-doc-$release.tar.gz | tar xz
+
+FROM debian:stretch
+ARG release
+ENV release=${release}
+RUN apt-get -y update && apt-get install -y \
+    libx11-6 \
+    libpng16-16 \
+    libfftw3-3 \
+    libcfitsio5 \
+    libforms2 \
+    python \
+    python-numpy \
+    python3 \
+    python3-numpy \
+    libgtk2.0
+RUN echo 'export GAG_ROOT_DIR=/gildas-exe-$release' >> /etc/bash.bashrc && \
+    echo 'export GAG_EXEC_SYSTEM=x86_64-debian9-gfortran' >> /etc/bash.bashrc && \
+    echo 'source $GAG_ROOT_DIR/etc/bash_profile' >> /etc/bash.bashrc
+COPY --from=builder /gildas-exe-$release .
+

README.md

-Build
-=====
+# Build
+
+## Two stages build
 
 Build the developpement image :
 
 ```bash
 export release=mar18c
-docker build -f Dockerfile.dev . --build-arg release=$release
+docker build --tag abeelen/gildas:build  --build-arg release=$release -f Dockerfile.dev .
 ```
 
-tag it
-```bash
-docker tag $release abeelen/gildas:build
-```
+extract the compiled files
 
-and make a tar from the files
 ```
-docker run -it -u $(id -u) \
-    -v "/home/$USER:/home/$USER" \
-    abeelen/gildas:build tar cvzf $PWD/gildas-exe-$release.tar.gz /gildas-exe-$release
+docker container create --name extract abeelen/gildas:build
+docker container cp extract:/gildas-exe-$release gildas-exe-$release
+docker container rm -f extract
 ```
 
+<!---
+extract the compiled files
+ ```
+ docker run -it -u $(id -u) \
+     -v "/home/$USER:/home/$USER" \
+     abeelen/gildas:build tar cvzf $PWD/gildas-exe-$release.tar.gz /gildas-exe-$release
+ ```
+--->
+
 Build the execution image :
 ```bash
-docker build -f Dockerfile . --build-arg release=$release
+docker build --tag abeelen/gildas:$release --tag abeelen/gildas:latest --build-arg release=$release -f Dockerfile .
 ```
 
-Finally tag this one
+## One stage build
+
+With Docker 17.05 or higher :
+
 ```bash
-docker tag $release abeelen/gildas:$release
+export release=mar18c
+docker build --tag abeelen/gildas:$release --tag abeelen/gildas:latest --build-arg release=$release -f Dockerfile.multistage .
 ```
 
+# Usage
 
-Usage
-=====
 
 To launch gildas, simply launch :