Add PyNaCl to setuptool's extras requirements.
Add PyNaCl to setuptool's extras requirements.

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