* NEW features for HistgramLUTItem
* gradientPosition=('left', 'right')
* only paint if item is visible (is faster)
* link hisogram to other histograms
* fixes to be able to merge
* drop linkHistogram (rgba needs to be better integrated)
* make sure defaults to same as current behavior
* draw connecting lines correctly on each side
* add example use
* 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