Pandalone

----------------------------------------------
+ DROP PY3.5 for it has no ordered dictionaries

+ replace the use of OrderedDict with vanilla (PY3.6) dicts.

+ FIX(pandel): treat np-arrays as booleans by checking their size, recommended
in `numpy/numpy9583 <https://github.com/numpy/numpy/issues/9583>`_,
to handle np.arrays's future boolean behavior (yet deprecated).

----------------------------------------
- FEAT(PANDEL): support auto defaulting/removing `nulls` with jsonschema validation.
- FIX(pandel): up-to-date patches to jsonschema for traversing pandas
(see `Julian/jsonschema675 <https://github.com/Julian/jsonschema/pull/675>`_)
- FEAT(CI): drop Python-3.5, test evenly, including Python-3.8.
- FEAT(build, doc): + ``[all]`` pip-extras (identical to ``[dev]``); document available
pip-extras in Quickstart section.
- enh(CI): Pytest-ize travis & appveyor scripts.
- enh(build): ignore folder when black-formatting, to eradicate delays when pre-commiting.
- fix(xleash.TC): up-to-date `pyeval` msg in a TC.
- enh(site): drop RTD mock hacks; fix `xlwings` intersphinx url.

----------------------------------------------
- fix xleash for pandas 0.25+ (19-July 2019).
- Pstep:

- enh: rename cstor 2nd arg from ``_proto_or_pmod --> maps`` and allow
to pass a sequence of 2-tuples to define mappings.
- feat: accept multiple tags at once.

-------------------------------------------------------------------------

--------------------------------------------------
- Support also asteval <0.9.10 (but still >0.9.7 needed for PY35+)

-----------------------------------------------------------
- Drop support for Python 2.7 & 3.4, `which covers 95% of 2018 Python-3 installations
(84% of Pythons in total)
<https://www.jetbrains.com/research/python-developers-survey-2018/python-3-adoption>`_
- Use latest jsonschem(draft7) for ``PandelVisitor``, using *jsonschema* lib,
bringing its lower-bound from 2.x.x --> 3.0.0.
- Fix *asteval* *xleash* filter to work correctly with latest version
using `usersym` table for context-variables (were missing those).
- Fix 13: ``ensure_filename()`` util were duping filename's file-extension
if was given the same.
- Build & dev-dependencies enhancements.
- Make all TCs to pass in both CIs for linux & Windows.
- Suport PyTest for launching tests - *nosetest* is still used in CIs,
an includes coverage also.
- style: auto-format python files with |black|_ using |pre-commit|_.
- Drop bloated documentation sections about installation and
cmdline-tools that never existed.
- Note: v0.3.0 were missing low-boundary on jsonschema >=3.

.. |black| replace:: *black* opinionated formatter
.. _black: https://black.readthedocs.io/
.. |pre-commit| replace:: *pre-commit* hooks framework
.. _pre-commit: https://pre-commit.com/