Add support for aiohttp connectors.
Add support for aiohttp connectors.

Fixes #98.

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