rollbot: don't direct slash-me messages in MUCs to anybody

rollbot: require sleekxmpp 1.3.3

rollbot: require PyYAML 3.12

docs: CC0 is also an option

rollbot: send some entity capabilities, why not

rollbot: add another command: snack

rollbot: no need to wait for MUCs If a user sends groupchat message to a room while the bot is still in the process of joining that room, the message will not be handled. And it shouldn't be, because the bot is not there yet! So there's no point in blocking the current thread on joining MUCs. Additionally, using wait=True triggers a warning: "Use of send mask waiters is deprecated." (from XMLStream.send)

rollbot: move logging options above main config, split the lines Helps keeping options and their defaults closer to each other.

rollbot: split a long line

rollbot: move logging below the lookups, split the line Helps keeping options and their defaults closer.