v0.4.1

Bug fixes:

• Fix CLI forcing default -r/-w/-c on file input via FFmpegAudioSource
• Fix Ctrl+C crash and audio glitches during playback with -E
• Quit correctly when -B is specified for audio playback with progress bar

Improvements:

• Refactor command line code and tests
• Show an error message when a command line argument appears more than once
• Make CLI help text 80-column max