Give the documentation some care and attention before 0.1

There are a bunch of things we probably want to incorporate into the docs since last time we did a big push to fix them up. An incomplete list:

• the bootstrap_with_* methods (!235 (merged)), which remove the need to use tor-rtcompat explicitly in the happy path
• the create_unbootstrapped mechanism (!298 (merged)) probably needs an example for how to use it

...probably more?