v10.0.0

Breaking changes:

• Raised Node.js minimum version to v8. This allowed us to remove the getOwnPropertyDescriptors polyfill in the generated utilities file, as well as the dependency on co. (#132, #134, @pmdartus)
• Removed support for old-style mixins. (#135, @pmdartus)
• Changed the [Reflect] implementation to use the setAttributeNS and getAttributeNS methods on the impl classes, instead of the wrapper classes. (#136, @pmdartus)

Other fixes:

• Fixed warning in the output about the "babylon" parser.
• Fixed the prototype of the [Symbol.unscopables] value to be null instead of Object.prototype, following the spec.