* [macOS] Adding QuickLook feature
* [macOS] Adding QuickLook support for Conda and Homebrew.
* [macOS] Support non-square app icons in thumbnails.
* [macOS] adding icon for .FCScript files
(this mostly aims at new modules and extension modules which want to use pip)
- any module having problems with nameclashes can use this syntax (from freecad import module)
- current imports still work (backward cobatibility)
- python extension moduels can be installed (pip) to python std path (eg.: site-packages)
- adding app, gui to the new freecad package:
```
from freecad import app
from freecad import gui
```
- syntax for importing c++ extension will not change
```
import FreeCAD as App
import FreeCADGui as Gui
```
