Detect if the Audio Files folder is in the trash

[latenitefilms]

Reported by Mark Terry.

Currently it's possible to send the "Audio Files" folder to the Trash, but BRAW Toolbox still writes the audio files to that folder, and references those files. This creates a FCPXML file that crashes Final Cut Pro.

We need to add logic to the BRAW Toolbox Workflow Extension to make sure the Audio Files folder isn't in the trash.