Remove the Python console

[ccordoba12]

This issue describes our reasons to remove the Python console from Spyder:

1. Broken on Windows: Executing code on it usually doesn't return the prompt. The situation is worst when Matplotlib integration is turned on because you have to press Enter several times to get a prompt back.
2. Matplotlib integration: Nowadays Matplotlib is tightly integrated with IPython and it's very difficult to have a different console with good Matplotlib support. Right now the only backend we are able to support in our Python consoles is the Qt one (not even Tk works!), and (as said above) it's broken on Windows.
3. Different implementations: We are a small project and don't have the resources nor the time to maintain two consoles with very different implementations (we're also in charge of qtconsole).
4. Debugging: It's not possible to detect when a Python console is running a debugging session, so we can't adapt certain functionality for debugging only (e.g. disabling buttons on the Debug toolbar).
   Besides, we plan to improve debugging in Spyder 4 by creating an IPbd kernel, so that users can run multiline code from the Editor, have code completion and history browsing while debugging. Unfortunately, this is something we can't support in the Python console.
5. History log: The history log is semi-broken because we can't make it work reliably for both consoles.
6. Not testable: It's not easy to add tests for the Python console because you can't tell for sure when the console is up and ready nor when it has finished a computation. That's why there are no tests for it right now.

---

TODO:

• Remove connection with the Variable Explorer - PR PR: Remove connection between the Variable Explorer and the Python console #4525.
• Remove connection with Help - PR PR: Remove connection between Help and the Python Console #4533.
• Remove connection with the Editor - PR PR: Remove connection between the Editor and the Python console #4541.
• Don't check for the presence of the IPython console (i.e. make it mandatory instead of optional) - PR PR: Remove connection between the Editor and the Python console #4541.
• Remove connections with the rest of plugins - PR PR: Stop loading the Python console #4549.
• Add Environment Variables and sys.path contents entries to the IPython console - PR PR: Add actions to show sys.path and environment variables contents to the IPython console #4562.
• Remove text about the Python console in the Run options dialog - PR PR: Implement dedicated IPython consoles #4691.
• Add Execute in a dedicated console option to the IPython console - PR PR: Implement dedicated IPython consoles #4691.
• Remove all code related to the Python console - PR PR: Remove all code related to the Python console #4713.
• Clean sitecustomize.py - PR PR: Remove all code related to the Python console #4713.

[koradir]

Will "Add Execute in a dedicated console option to the IPython console." once implemented still resolve issues like
https://stackoverflow.com/questions/38042329/python-kivy-app-running-only-once
?

[ccordoba12]

Yes, I think so because the kernel will be restarted every time on a dedicated console.