This change makes use of QPointF methods which perform faster than the python
equivalent methods. Furthermore, some tests are added.
* Set __slots__ to empty tuple for pg.Point
* Make Point.angle() behave as Vector.angle()
* 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