Contiker: Contiki-NG's Docker image

[simonduq]

This PR brings Docker support for the NG toolchain and development environment (Dockerfile under tools/docker). It also uses the Docker image in Travis tests, so that one can exactly reproduce the Travis environment locally. It builds on #165 for cleaner CI tests, and reworks the CI framework further. More consistent scripts across the tests, and more readable test logs.

I have tested this on a Linux 64-bit host. The Docker image builds from a 32-bit Ubuntu, as required for Cooja "Contiki motes".

To get started, you can either build the image or download it from Docker Hub. To build it:

cd contiki-ng/tools/docker
docker build -t contiki-ng .

To download it:

docker pull simonduq/contiki-ng

For convenience, one can use an alias such as (tested only on Linux):

export CNG_PATH='<ABS_PATH_TO_YOUT_CONTIKI_NG>'
alias contiker="docker run --privileged -v $CNG_PATH:/home/user/contiki-ng -e DISPLAY=$DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix -ti simonduq/contiki-ng"

The container uses a bind mount to directly access the Contiki-NG repo form the host. This is what Travis uses (it git clones on the host, then starts a container with direct access to the cloned git). This is also handy as a development environment, as it leaves the Contiki-NG git clone no the host, i.e. accessible by editors installed in the host.

We also provide as an alternative a standalone image, with Contiki-NG and pre-compiled Cooja included. The image is also on Docker Hub, just pull simonduq/contiki-ng:standalone.

With the alias above, one can then start a bash:

contiker bash

or even just:

contiker

Run a particular command:

contiker bash -c "make -C examples/hello-world TARGET=zoul"

Or even run Cooja directly, provided one has a X server running on the host, and DISPLAY points to it:

contiker cooja

There is one particular 6top test that does not pass. @yatch , any clue what the problem might be?
https://travis-ci.org/simonduq/contiki-ng/jobs/303194585

To reproduce:

docker pull simonduq/contiki-ng
contiker bash -c "make -C tests/16-6tisch 02-cooja-test-sixp-pkt.testlog"

Or contiker cooja, open and run the 02-cooja-test-sixp-pkt.csc.

[simonduq]

6top problem solved, thanks @yatch !