v0.1.8

• Fix: implement query.batch() as async iterator
• Fix: NOT (expr)
• Fix: IFNULL(foo, default)
• Fix: support .select(name[]), .select(name => {}), and .select("...name")
• Docs: Model => className in association options
• Docs: use jsdoc to generate docs/api
• Docs: .include()
• Docs: 中文文档