Release jul20

[cpascual]

This is a PR to master for the official Jul20 release. Final tests (automatic and manual) should be done based on it before accepting the merge.

So, this is a call for help from @taurus-org/integrators and any other person willing to help to test this branch ASAP in their respective systems.

Environments in which the manual tests should be done (please leave a comment if you volunteer to do the tests in one of them or in some other)

• [x] Debian9, py2qt4 (using debian packages for the dependencies) Done by @cpascual in #1138
• [x] Debian10, py3qt5 (using debian packages for the dependencies): Done by @cpascual in #1128
• [x] Win10 py3qt5 (using conda packages for the dependencies): Done by @cpascual in #1134
• Some GNU/Linux system with up-to date conda environment and latest py3.7 conda dependencies Nobody took the task, so it won't be done
• ... any other would be very welcome

(please let us know in the comments of this PR if you plan to do some more manual tests)

Notes:

1. A suggested check-list for the manual tests can be found in /doc/how_to_release.md
2. the appveyor artifacts from this PR (use the latest ones) should be used for manual tests (they are preferred to using the git sources, because the git sources may contain files that are not in the artifact).
3. The taurus-test docker images may be useful for testing on debian
4. If you do a full check using the check-list, please open an independent issue in order not to spam this PR with long comments (see e.g. #959 )
5. If you want to paste long logs, consider using a gist for that.
6. Please consider creating issues to report individual bugs found during the manual tests
7. If some part of the check list needs to be amended, consider creating a PR with the changes
8. Make sure to use taurus_pyqtgraph >= 0.3.5

[cpascual]

IMHO, this is ready to be released.

It would be great if other @taurus-org/integrators (specially from MAXIV, Solaris, Desy,.. ) review it and give a green light

[cpascual]

Given the lack of availability from other @taurus-org/integrators during this release, I do not expect any review coming, and therefore it makes no sense to continue delaying it. I am going to merge without peer-review.

And please, have a look at #1140