Make the procedure for setting the source content of a player unbind from the previous player

This fixes #40

Generated from:

commit e96a71eb626d6109d25869e7e94a368186f5d0a0
Author: Brian Birtles <birtles@gmail.com>
Date:   Tue Dec 16 16:38:48 2014 +0900

    Make the procedure for setting the source content of a player unbind from the previous player

    This fixes #40