Include libsass instead of node-less

Thank you to @d-fence for testing this.

We should normally stick as close as possible to the version we depend
on in the official DEB packages. This in turn depends on the version of
Debian stable at the time of release - for 9.0 that would be Debian 8
(jessie) and thus Pillow 2.6.1.

However Pillow versions before 3.1.1 suffer from a few issues that could
lead to crashes of Odoo workers. The bugfixes have been backported in
the DEB packages for Pillow, so users of Debian/Ubuntu LTS versions
won't be affected if they are keeing their systems updated.

However it's worth an exception to our rule for pip users.

FWD-PORTS: skip

problem: installing from the source on windows includes manual modification of the requiremnets, as well as
not supported package versions

solution:
- increased the version of lxml, werkzeug and pillow to the latest supported version in debian, it
will fix already a number of issues on windows
- automatically include or exclude dependencies from requirement.txt using requirement specifiers

Note that for lxml on windows, we will always install the latest version because the version 3.7.1 does not exist on
windows in WHL.

Follow up of e419f395
pyscopg 2.7.3 does not work with glibc 2.66
2.7.3.1 is the minimum one

Courtesy of Laurent Mignon, Acsone, #19512

2.7.1 is broken with glibc 2.66
upgrading to latest working version: 2.7.3
cf psycopg/psycopg2-wheels#2

Add CLA

Fixes #19511
Closes #19512

Upgrade the dependency for ebaysdk from 2.1.4 to 2.1.5.
There was a bug in in 2.1.4 that prevented installing (see https://github.com/timotheus/ebaysdk-python/issues/223).
Closes #20148 

Purpose: openid is not used anymore in Odoo, therefore it can be
safely removed.

Purpose:
    The psycogreen module is unmaintained. Last source update was in
    2015 and last pypi package was in 2012. Odoo only use a small
    part of the psycogreen module that could be written directly in
    the odoo code. This commit reproduce the small function from
    psycogreen used in ODoo and remove all depencies from it.
    Also the copyright and license are honored and the documentation
    is updated accordingly.

    pypi pckage: https://pypi.python.org/pypi/psycogreen
    bitbucket repos: https://bitbucket.org/dvarrazzo/psycogreen/

* gitignore pycache folders (apparently appear for some)
* update xlwt requirement: 1.1.2 does not work with Python 3.6, 1.2 should work, 1.3 officially supports it

- jcconv is not P3-ready and is only optional, for use on the POSBox
  firmware for Japanese charset support in some receipt printers
  (The POSBox firmware is still based on Odoo 8 + PY2 at this time)

- wsgiref is built-in since Python 2.5, and the one on pypi does not work
  on Python 3.2+

Version 2.7.1 is not yet available in most distributions,
but is now considered the recommended version.

Odoo will work just fine with any psycopg2 version >= 2.2, though.

update ofxparse to 0.16: fix language issues

closes #15713

The vendored html2text is *really* old and absolutely not
P3-compatible.

There is a maintained version on Pypy which is, so use that and stop
vendoring html2text.

PyPDF is unmaintained and abandoned (as noted on its home page
http://pybrary.net/pyPdf/) and was never updated to Python 3. PyPDF2 is
a fork which provides a mostly compatible API and is P3-compatible.

Replace PyPDF by PyPDF2.

- RML Reports
- Webkit Reports (most part already removed by 13b9982c)
- LocalService in netsvc.py
- rename attributes like rml_% to report_%
- rename ir.actions.report.xml to ir.actions.report
- allow rendering directly on an ir.actions.report by calling render method
- remove 'controller' report_type
- remove unused res.font stuff
- remove print_report method in models.py (not used)
- restore removed call to pdftotext process in test_reports

* LDAP import: python-ldap is not python3-compatible, pyldap is

  Warning: only supported from debian Stretch (current testing)?
  https://packages.debian.org/search?searchon=names&keywords=pyldap

* implicitly relative imports
* imports of moved or removed stdlib modules

issue #8530

Needed to import xlsx files

Closes #15644

In order to circumvent https://bugs.launchpad.net/lxml/+bug/1625506

closes #13721

The stdlib version of the json library is more recent than the 3.5.3
version we are pinning in `requirements.txt`

There is no reason to use it.

Closes #6940

The `unittest2` package is simply a backport of `unittest` from the
Standard Library of Python 2.7 to previous versions.

There is no reason to use it any longer.

Closes #6941

gevent 1.0.1 (old) causes issue on Debian 8.0 Jessie : Disk running out of free space
Cause: /var/log/syslog and /var/log/daemon.log full of "NameError: name 'PROTOCOL_SSLv3' is not defined"

FYI: disk of 20GB runs out of space in less than 24h!

gevent 1.0.2 release notes : https://github.com/gevent/gevent/blob/1.0.2/changelog.rst#release-102-may-23-2015

switch to reportlab 3.1.44 because of install problems with 3.1.8
(See https://bitbucket.org/rptlab/reportlab/issues/55/setuptools-80-cannot-install-reportlab-318 )

Workarounded https://launchpad.net/debian/+source/openssl/1.0.1j-1 by updating
requests in requirements.txt and pip in our tests environment.

This library is a SOAP client. It will be used to integrate Odoo with
external web services that use SOAP based protocols.

PyChart 1.39 is available on pypi.python.org, use it
in dependency specs instead of the direct link to
unreliable download.gna.org

Closes #6781

While calling `pip install -r requirements.txt`, the PyChart tarball is
always downloaded even if `pip` has a download cache configured (which
it does by default in later versions).

This is because `pip` has no way of knowing which package the PyChart
tarball contains before downloading and running its `setup.py`.

By declaring the PyChart "egg" in `requirements.txt` the tarball is no
longer downloaded if it's already in the download cache.

It is never used in the code, and causes problems with wheels: related
to pypa/pip#2105

closes #3744

[FIX] requirements.txt: add info about optional python requirements used for the point of sale receipt printing