Migrating tests to ES6 because generators!
ADDED browser.link(selector, text, url, message)
ADDED browser.focus(selector)

- Changed focus on the element
- When switching focus between controls, fires change event
CHANGED browser.fill() emits input, sometimes change event

- browser.fill() changes focus to field in question
- emits input event (HTML5)
- changes focus out of field
- if value changed, this will also emit change event
- no longer emits key/mouse event