Add voice playlist example code.
Add voice playlist example code.

rapptz/discord.py,Harmon758/discord.py,mgardne8/discord.py,variablehair/Eggplantato,imayhaveborkedit/discord.py,jhgg/discord.py,Rapptz/discord.py,Theoretical/UselessBot,Harmon758/discord.py,lgkern/PriestPy,khazhyk/discord.py