Semi-update readme
Semi-update readme

A bit more work. I'm pretty sure calling it `:dojo` is more appropriate than `+dojo` since it is neither a dog nor a cat, like how we call it `:talk` instead of `+talk`.

I also rewrote some old sections, but not very well. Grep for "XX" to see what needs improvements...
ohAitch/urbit,ngzax/urbit,juped/your-urbit,ngzax/urbit,juped/urbit,cgyarvin/urbit-1,juped/your-urbit,max19/urbit,juped/your-urbit,max19/urbit,max19/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,juped/urbit,juped/your-urbit,cgyarvin/urbit-1,ngzax/urbit,juped/urbit,cgyarvin/urbit-1,jfranklin9000/urbit,juped/urbit,jfranklin9000/urbit,max19/urbit,ohAitch/urbit,cgyarvin/urbit-1,urbit/urbit,juped/your-urbit,juped/urbit,jfranklin9000/urbit,juped/your-urbit,ohAitch/urbit,ohAitch/urbit,jfranklin9000/urbit,max19/urbit,ohAitch/urbit,juped/urbit,ohAitch/urbit,max19/urbit,ngzax/urbit,cgyarvin/urbit-1,cgyarvin/urbit-1,urbit/urbit,urbit/urbit,ohAitch/urbit,cgyarvin/urbit-1,urbit/urbit,ohAitch/urbit,jfranklin9000/urbit,juped/your-urbit,jfranklin9000/urbit,juped/urbit,jfranklin9000/urbit,max19/urbit,ngzax/urbit,juped/your-urbit,ohAitch/urbit,juped/your-urbit,max19/urbit,cgyarvin/urbit-1,juped/your-urbit,juped/urbit,urbit/urbit,ohAitch/urbit,urbit/urbit