Fix deadlock if encoder never received a picture
Prevent and warn about excessive audio buffering
Fix audio thread deadlock and issues with PTT / mute
Use FindWindow for DWM monitor capture

Because the DWM window is an invisible window, the recent change using
FindVisibleWindow instead of FindWindow will cause it to never find the
DWM window.  So, detect if the target is the DWM, and then use regular
FindWindow instead if so.
Fix scene collection loading at startup
Keep Global Sources in "sceneCollection/scenes.xconfig".

Instead of each Scene Collection having its own Global Sources. They are stored in and read from "sceneCollection/scenes.xconfig".

With this change users won't need to recreate their Global Sources for every new Scene Collection.

When a user deletes a Global Source it is removed from all Scene Collections.

The only issue I know is when a user renames a Global Source the user will need to add it back to the scene.