v7.0.0

• Potentially breaking: improve handling of semitransparent pixels. Previously, they were blended with white, so a transparent pixel vs white pixel would show zero difference; now pixels are blended with an irregular pattern, making it easier to catch regressions. (h/t @NathanMOlson #142)
• Improve match performance by ~6%. #147
• Significantly improve diff generation performance. (h/t @kawanet #105)
• Fix options handling to use the default value when undefined is passed explicitly. (h/t @denis-sokolov #146)
• Fix ESLint failing on Windows when working on the library locally. (h/t @haraldreingruber-dedalus #123)