Using the `nofail` argument and hooking to `login` event, one can make
as much modules unittests as possible run, and skip the unittests which
require authentication or special configuration.

Tests are also run using all available backends now. This is especially
important for modules such as Amazon for which the backend has a large
influence on the website being used and the code being run.

I also changed the default values so that they match the expected type
(rather than being `None`).

* Sort alphabetically modules in weboob linting script
* Remove btdigg module, as btdigg website is dead.
* Add icons for all modules with a missing icon.
* Add some unittests for LDLC.

This commit adds the necessary files to run the CI using Gitlab-CI. For
now, it checks that Weboob builds, then runs the linting script
(checking that every module as an icon and some tests + PyFlakes) and
the unittests. Most of modules unittests cannot run because there is no
backend configured.

Some changes were needed in the pre-existing scripts:
* Edit `weboob_lint` to exit with non-zero code if it finds modules
without icons or tests, so that the build could fail in such a case.
* Edit `run_tests.sh` to set correct exit code on failure and rework
generation of XUNIT output. Also added some doc about useful environment
variables. Added a way to generate an xunit output file when running modules
unittests, passing a `XUNIT_OUT` env variable to `run_tests.sh` script.
* Modification of `setup.cfg` and `run_tests` scripts to handle code
coverage generation. The matching regex in Gitlab for the total code
coverage is `TOTAL: (\d+\%\s*)$)`.

I also added a script to generate a JSON module status matrix from
modules unittests, ready to be sent to a
[Weboob-CI](https://github.com/Phyks/weboob-ci) instance.

NOTE: Required Python modules are taken from the `setup.py` script.
`.ci/requirements.txt` contains the requirements to run the unittests
and the CI, whereas `.ci/requirements_modules.txt` contains the specific
Python modules required at runtime by Weboob modules. The latter could
eventually be replaced by a proper call to `debpydep` script.

Today, I got this error message:

Error(ing): Dates importantes pour la fin d'année 2016

It does not really helped me to understand what to do.

Romain Bignon authored Nov 30, 2016 and Romain Bignon committed Dec 03, 2016

This reverts commit 0b3db442c996a3b8ded47963ad07c58adda1b2d5.