Release v1.0.9

• node: move Image type to image.Image, and remove depth filed, stride is optional
• node: move png/jpeg helper function to helper module
• support travis-ci build
• more unit test
• add bench test

Release v1.0.8

• fix bin/guetzli-cli on darwin

Release v1.0.7

• try fix bin/guetzli-cli

Release v1.0.6

• try fix npm install

Release v1.0.2

• switch to TypeScript
• support browser
• add encodeImage
• add online example
• more docs