support hidden attribute and internal refactoring

v0.9.1 (2018-07-05)

Full Changelog

Closed issues:

• "Attempting to change value of a readonly property" on Safari 9 #87
• misaligned if parent initially hidden #86
• Cleanup/Refactoring #71

Merged pull requests:

• Move babel-eslint to dev dependencies #89 (Turbo87)
• feat(api): support hidden attribute #85 (jamesarosen)
• refactor(legacy support): use unified component #83 (simonihmig)