- removed unused import statements

- added macOS specific required library to requirements.txt
- conditional import of pygrabber, which is unavailable for macOS

modules/ui.py

@@ -12,6 +12,7 @@ import pyvirtualcam
 if platform.system() == 'Darwin':  # macOS
     import AVFoundation
 
+# Import Windows specific modules only when on windows platform
 if os.name == 'nt':  # Windows
     from pygrabber.dshow_graph import FilterGraph