This seems to fix the flicker

[almarklein]

• Fixes the flicker (Regression for custom get_context() integrations (v2.4.0) #137)
• Updates utils/cube.py to use low-power adapter to select intel driver.
• Update cube_qt.py to easily switch between bitmap and screen.

It looks like once paintEngine returns something, qt goes with that, so we should not default to returning the normal engine. This will at least make 'screen' work. For 'bitmap' it looks like paintEngine is never even called (?)

Would be good to test this out on a few systems and platforms.

If this works, I'll merge async-bitmap and prepare a new pr with the fix (but it will be a bit different).

[Vipitis]

Update cube_qt.py to easily switch between bitmap and screen.

I wonder if it could work with putting two canvas widgets in the app, one presenting as screen and the other as bitmap? might be an easy way to compare responsiveness for example.