Remove Master and Slave from Code Base and Docs

Every time I read master and slave, I get pissed.

I think about the last and only time I remember visiting my maternal great grandpa in Alabama at four years old. He was a sharecropper before WWI, where he lost his legs, and then he was back to being a sharecropper somehow after the war. Crazy, I know. I don't know if the world still called his job sharecropping in 1993, but he was basically a slave—in America. He lived in the same shack that his father, and his grandfather (born a slave) lived in down in Alabama. Believe it or not, my dad's grandfather was actually born a slave, freed shortly after birth by his owner father. I never met him, though. He died in the 40s.

Anyway, I cannot police all terms in the repo and do not wish to. This master/slave shit is archaic and misleading on technical grounds. Thankfully, there's only a handful of files in code and documentation that still talk about masters and slaves. We should replace all of them.

There are so many ways to reword it. In fact, unless anyone else objects or wants to do the grunt work to help my stress levels, I will open the pull request myself in effort to make this project and community more inviting to people of all backgrounds and histories. We can have leader/follower, or primary/secondary, but none of this Master/Slave nonsense. I'm sick of the garbage.