Significant performance issues have been identified with np.clip
and thus clip_array was created to speed up the operation. In addition
clip_scalar was created to clip a scalar value between two other values
this commit replaces many uses of np.clip from operating on scalars to
using clip_scalar instead
* 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