adding the possibility to log to stdout

adding (mostly) working configuration example

another exception

another exception

another exception

wider exception for <input> attribute "type" has invalid value

another exception for todylib

adding another ignore

another ignore for tidylib

adding a fffew other exception in tidylib

fix typo

html_tidy cleanup

ignoring another nav error

adding exception for <nav> tags in html validation

cleanup in html template + tidylib ...

* few small cleanup in html template (avoid empty tbody, put id between
quotes)
* switch to tidylib to validate the html instead of the previous hack
calling an external service (https://html5.validator.nu/)
* remove the previous validator script
* add exception for tidylib on empty <span> (these are required by
bootstrap)

fix html validator test for python 3

force the groups in flatten roles to be sorted ...

* sorting the groups helps debuggability and also permits testing
that doesn't rely on python ordering (which is different between 2 and
3).

fix test and exception handling in code ...

With python 2 it was possible to do exception[0][...] to recover
details about an exception.
It's no longer authorized with python 3.
Now, we must do something like exception.args or exception.urls.
fortunately this syntax also works with python 2.
So we use it for both.

fix behavior of get_attributes() ...

* make sure it returns an ordered list in both python 2 and python 3

disable ppolicy in samba test deployment

trying to fix samba/AD setup

adding another samba package in test env

adding another dependency for the samba/ad test

fixing the test env deploy script + small fix in unit tests

add requirements files for simulating RHEL 7 and Debian 9

porting the tests over to python3

adding an update as the first step of the deploy script

slightly cleaner testenv deploy script

remove useless tests

small cleaning