v2.0.0

Change:

• ➖ No longer add Promise polyfill (es6-promise) for you.
  Now, you have to add Promise polyfill yourself if you need.
• ➖ Remove unfetch polyfill (for fetch).
• ✨ Use axios to instead of fetch.
• 🔧 Move octicons from dependencies to devDependencies.
  • 💩 And extract only necessary icons to SVG files.

Development:

• Use Poi to create preview page for development.
• Use SVG files as Vue component. (Thanks svg-to-component-loader)