Made ``utils.which`` work for windows systems, where executables have a ".exe" extension. Removes warning for not finding ffmpeg or avconv even though they are installed for windows systems.
Made ``utils.which`` work for windows systems, where executables have a ".exe" extension.
Removes warning for not finding ffmpeg or avconv even though they are installed for windows systems.

Geoion/pydub,miguelgrinberg/pydub,joshrobo/pydub,sgml/pydub,jiaaro/pydub,cbelth/pyMusic