Docs: Attribute / method table for classes

[Hunter2809]

https://github.com/Rapptz/discord.py/blob/master/docs/extensions/attributetable.py https://discordpy.readthedocs.io/en/latest/api.html Making the docs look like these can help navigate better!

[einarf]

Getting the methods and attributes seprated is a really good idea. I was trying to make that work with order in sphinx recently, but this seems to be way better.

[pvcraven]

Ho man, finally on desktop and those docs are pretty.