* Improve HistogramLUTItem docs, a few cosmetic changes
* Initial implementation of horizontally-oriented HistogramLUTItem
- Also adds support in HistogramLUTWidget
- Fixes AxisItem orientation bug for vertical orientation
- Make use of GradientEditorItem orientation (fixes another bug for
vertical orientation)
- Use horizontal orientation in an example for demonstration
* Remove unused HistogramLUTItem option
* A few more minor fixups
* Copy paste bug
* Use f-strings
* Update from review and a couple more minor updates
* Woops
* Add doc for orientation arg
* Add top/bottom orientation to doc. Expand on levelMode doc a bit
* set environment variables before starting QApp
* fix-422
* Better support of hidpi
* Fix Typo in App-Name
* Remove fontScaleFactor bits
* Add documenation for hidpi displays
* Fix pg not defined
* set environment variables before starting QApp
* fix-422
* Better support of hidpi
* Fix Typo in App-Name
* Remove fontScaleFactor bits
* Add documenation for hidpi displays
* Add NonUniformImage, example and tests.
* Use updated test-data tag
* Fix line ending, remove lut.setLevels keyword arguments call
Co-authored-by: Ogi <ognyan.moore@gmail.com>