Add more integration tests

[julianandrews]

I should add a bunch of integration tests.

At a minimum, I'd like to test move numbers, markup, node selection, and different styles.

Probably it makes sense for all the examples I'm currently using in the README to come straight from the integration tests.

[julianandrews]

Checklist:

• [x] node by number
• [x] shrink wrap
• [x] full board
• [x] explicit range
• [x] no board labels
• [x] last node
• [x] numbered moves
• [x] numbered moves starting at a number
• [x] explicit width
• [x] markup
• [x] different style