Explain release process with pypi and wheels.

Just putting indentation and "::" in front of everything.

This is a first step in trying to make syntax error messages more useful.

For this faulty RQL:

    DISTINCT Any N WHERE N is Network, N type "cold water", FCC calibration_for N, FCC variables ILIKE "%conso%", FCC in_state SFCC, FC use_calibration FCC, FC in_state SFC, SFC name "wfs_finished", FC prediction_date FCB, FC nhours FCH, FCP calibration_for N, FCP variables ILIKE "%prod%", FCP in_state SFCP, FP use_calibration FCP, FP in_state SFP, SFP name "wfs_finished", FP prediction_date FPB, FP nhours FPH, MAX(FCB, FCP) < MIN(FCB + CAST(Interval,CAST (String,FCH)+" hours"), FPB + CAST(Interval,CAST(String,FPH)+" hours"))'

It will turn the error message from:

    RQLSyntaxError: DISTINCT Any N WHERE N is Network, N type "cold water", FCC calibration_for N, FCC variables ILIKE "%conso%", FCC in_state SFCC, FC use_calibration FCC, FC in_state SFC, SFC name "wfs_finished", FC prediction_date FCB, FC nhours FCH, FCP calibration_for N, FCP variables ILIKE "%prod%", FCP in_state SFCP, FP use_calibration FCP, FP in_state SFP, SFP name "wfs_finished", FP prediction_date FPB, FP nhours FPH, MAX(FCB, FCP) < MIN(FCB + CAST(Interval,CAST(String,FCH)+" hours"), FPB + CAST(Interval,CAST(String,FPH)+" hours"));
    at: ('<f.3664>', 1, 414)
    Trying to find one of QMARK, R_TYPE, CMP_OP, 'IN'

To:

    RQLSyntaxError: Trying to find one of QMARK, R_TYPE, CMP_OP, 'IN' in:
    DISTINCT Any N WHERE N is Network, N type "cold water", FCC calibration_for N, FCC variables ILIKE "%conso%", FCC in_state SFCC, FC use_calibration FCC, FC in_state SFC, SFC name "wfs_finished", FC prediction_date FCB, FC nhours FCH, FCP calibration_for N, FCP variables ILIKE "%prod%", FCP in_state SFCP, FP use_calibration FCP, FP in_state SFP, SFP name "wfs_finished", FP prediction_date FPB, FP nhours FPH, MAX(FCB, FCP) < MIN(FCB + CAST(Interval,CAST(String,FCH)+" hours"), FPB + CAST(Interval,CAST(String,FPH)+" hours"));

    at line 1 and column 414
    around: ...n_date FPB, FP nhours FPH, MAX(FCB, FCP) < MIN(FCB + CAST(In...
                                             ^ here

Similarly, for this RQL (the same but on several lines):

    DISTINCT Any N WHERE N is Network, N type "cold water",
    FCC calibration_for N, FCC variables ILIKE "%conso%",
    FCC in_state SFCC, FC use_calibration FCC,
    FC in_state SFC, SFC name "wfs_finished",
    FC prediction_date FCB, FC nhours FCH,
    FCP calibration_for N, FCP variables ILIKE "%prod%",
    FCP in_state SFCP, FP use_calibration FCP,
    FP in_state SFP, SFP name "wfs_finished",
    FP prediction_date FPB, FP nhours FPH,
    MAX(FCB, FCP) <
    MIN(FCB + CAST(Interval,CAST(String,FCH)+" hours"),
        FPB + CAST(Interval,CAST(String,FPH)+" hours"));

It will turn the error message from:

    RQLSyntaxError:   1: DISTINCT Any N WHERE N is Network, N type "cold water",
       2: FCC calibration_for N, FCC variables ILIKE "%conso%",
       3: FCC in_state SFCC, FC use_calibration FCC,
       4: FC in_state SFC, SFC name "wfs_finished",
       5: FC prediction_date FCB, FC nhours FCH,
       6: FCP calibration_for N, FCP variables ILIKE "%prod%",
       7: FCP in_state SFCP, FP use_calibration FCP,
       8: FP in_state SFP, SFP name "wfs_finished",
       9: FP prediction_date FPB, FP nhours FPH,
      10: MAX(FCB, FCP) <
      11: MIN(FCB + CAST(Interval,CAST(String,FCH)+" hours"),
      12:     FPB + CAST(Interval,CAST(String,FPH)+" hours"));
    at: ('<f.3665>', 10, 4)
    Trying to find one of QMARK, R_TYPE, CMP_OP, 'IN'

To:

    RQLSyntaxError: Trying to find one of QMARK, R_TYPE, CMP_OP, 'IN' in:
      1: DISTINCT Any N WHERE N is Network, N type "cold water",
      2: FCC calibration_for N, FCC variables ILIKE "%conso%",
      3: FCC in_state SFCC, FC use_calibration FCC,
      4: FC in_state SFC, SFC name "wfs_finished",
      5: FC prediction_date FCB, FC nhours FCH,
      6: FCP calibration_for N, FCP variables ILIKE "%prod%",
      7: FCP in_state SFCP, FP use_calibration FCP,
      8: FP in_state SFP, SFP name "wfs_finished",
      9: FP prediction_date FPB, FP nhours FPH,
     10: MAX(FCB, FCP) <
     11: MIN(FCB + CAST(Interval,CAST(String,FCH)+" hours"),
     12:     FPB + CAST(Interval,CAST(String,FPH)+" hours"));

    at line 10 and column 4
    around: MAX(FCB, FCP) <
               ^ here

Closes #17256169

There's no good reason to include debian packaging in python sdist.

This allow pip to install a older python2 compatible package if running with python2.
The "Programming Language :: Python :: 3 :: Only" is just for pypi statistics AFAIK.

We're going to remove python2 support so we can remove six as well.

This script is used to publish wheel binary packages to pypi.
Since we're going to remove python2 support, stop generating wheels for python2.
Also py38 is out and our wheel doesn't compile with py38 due to a bug of logilab-common.
Waiting a fix, don't build wheel for py38.

% docker run --rm -it quay.io/pypa/manylinux1_x86_64 ls -1A /opt/python
cp27-cp27m
cp27-cp27mu
cp34-cp34m
cp35-cp35m
cp36-cp36m
cp37-cp37m
cp38-cp38

This packaging (if it works) only work for python2 and we're going to drop
python2 support.
I don't have an rpm build environment and I don't known how to test this, so
just drop the spec file and let someone revive this if needed.

Various improvements to Debian packaging:

 - Depend on python-yapps and python3-yapps for YAPPS runtime.
 - Use PYBUILD_NAME instead of debian/*.install files.
 - Use python3-sphinx instead of obsolete Python 2 version.
 - Always build Python 3 package.
 - Run tests at build time and adds relevant packages to Build-Depends.
 - Add superficial autopkgtest using autodep8.
 - Add autopkgtest script to run unittest against installed packages.
 - Add Vcs-Hg and Vcs-Browser fields.
 - Update Standards-Version to 4.3.0.

In order to run the tests at build time and with autopkgtest, they need
to be made part of the Python source package. The manifest has been
modified accordingly.

Special cases:
    - `long` and `unicode` no longer exist in python 3. I added a "# noqa"
      comment to avoid warnings.

    - `cmp` method no longer exist in python 3. It was used in the
      `test/unittest_analyze.py` file in the __cmp__ method. It appears that
      when this method is removed, all the tests are still valid. Therefore I
      dropped it.

Fixing E402 implied running autopep8 for :
     - E404 from __future__ imports must occur at the beginning of the file
     - E303 too many blank lines