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

adding posixGroups in test ldap

fix test configuration

trying to add test on AD/DC for travis

improve robustness if user dn attribute contains something like ,cn=

better behavior if user doesn't exist in one backend

fix AD test configuration

code multi-backends setups tests + new unit test ...

* add a ldap+ad setup and code for direct, only AD manipulation
* add unit test for _deleteuser if it doesn't exist in all backends

adding configuration for AD + LDAP setup

disable unit tests for AD on travis ...

Setting up a test env with samba 4 as AD doesn't seem possible on
travis. there is no other choice than disabling the AD unit tests
if we are on travis

adding slow_disabled decorator on html check unit tests

adding a decorator to disable slow tests ...

if env var LCNOSLOW=yes, the slowest tests are disable

adding unitests for backend AD