Co-authored-by: NTakeshi KOMIYA <i.tkomiya@gmail.com>

This completes the migration from the CONTRIBUTING document to the new
in-tree contributing guide. The CONTRIBUTING document itself is
temporarily removed so that git will correctly mark the document as
having been moved. A future change will re-add this document as well as
rework the new contributing document.
Signed-off-by: NStephen Finucane <stephen@that.guru>

Fixes:

    README.rst:: (ERROR/3) Anonymous hyperlink mismatch: 10 references but 11 targets.

* Close #6658: Add CODE_OF_CONDUCT

* #6658 refine CoC

* Base on Django CoC: https://www.djangoproject.com/conduct/
* Simplify: we are a smaller project and can be more concise
* Add to ToC
* Link from README
* Link from index page

As spelled on https://pypi.org/.

As spelled on https://pypi.org/.

Readthedocs status is shown as `docs unknown` before this change because any version is specified on image url.

For details on the new PyPI, see the blog post:

https://pythoninsider.blogspot.ca/2018/04/new-pypi-launched-legacy-pypi-shutting.html

This necessitates adding some basic coverage-py configuration [1] and
making sure the pytest-cov plugin uses said configuration [2]. Badges
are included.

Note that we do not run the 'coverage' tox target, which is reserved for
users.

[1] https://github.com/codecov/example-python
[2] https://bitbucket.org/ned/coveragepy/issues/512/Signed-off-by: NStephen Finucane <stephen@that.guru>

Signed-off-by: NStephen Finucane <stephen@that.guru>
Fixes: 393f59da ("Improve README")

Add AppVeyor badge and include 'alt' attributes for the others.
Signed-off-by: NStephen Finucane <stephen@that.guru>

We're going to be adding additional badges to this but, before we do
that, we should improve the README and remove a lot of the duplication
that has built up here.

The 'long_description' from 'setup.py' is moved into the README as there
is serious value in displaying this on GitHub, as much as there is value
in including the badges and other content from README.
Signed-off-by: NStephen Finucane <stephen@that.guru>

Also, avoid a redirect, by specifying target URL.