Anki add-on: Bluetooth Headset Audio Lag Fix

When using a bluetooth headset, you may experience a lag at the start of a song (especially at the start of the audio of anki cards). This is due to the fact that headset are in sleep mode when they do not receive any song from the computer, and when they receive a song they take almost one second to wake up and play the song (which correspond to 1 or 2 word in Anki card). This addon simply plays continuously a silent song to keep the headset connected and avoid this lag. It works with mpv or mplayer lib (exactly like Anki) so if Anki audio works, this addon should work. Enjoy :)