Customizable buttons & formats
Buttons are now defined in an array called buttons
at the top of the script
Add or remove as many buttons as you like
The name of the button is the name of the format that will be downloaded (not case sensitive)
Many audio formats are supported, but MP4 is the only video format (for this script)
The download function has been moved down to the main script to avoid an unnecessary declaration
Removed yt.clit.repl.co usage due to its extreme instability. All buttons will use loader.to, even though its MP3s are slightly larger.