Bump libres version in CI to 4.1.0

Add refcase and history to statistics plot

Update 2.11 release notes with GEN_PARAM fix

Add csv_export2 as a bullet in semeio release notes

Bump libres to 4.0.1

Add release notes for 2.11

Fix plotting with empty storage

Python 2: Use io.open to save ERT config

Source: https://stackoverflow.com/questions/6048085/writing-unicode-text-to-a-text-file

As far as I understand, Python 2's `open` will by default try to convert `unicode` (which I verified is what `self.ide_panel.getText()` returns) into Latin-1 or `ascii`. We use `io.open`, which in Python 3 is the same as the builtin `open`.

Fix run_context being None in run_model

Logarithmic scale handling

- Fix key_def test
- pair programmed with @lars-petter-hauge