* Desugar class properties to Object.defineProperty per spec
* Define uninitialized static class properties with value=undefined
* Make class-properties increased spec compliance opt-in (spec: true)
* Support computed class property names (#4499)
** Depends on babel/babylon#121 **
* `babel-types`: Add `computed` field to `ClassProperty`
* `babel-plugin-transform-class-properties`: handle computed property names correctly
* `babel-generator`: add tests for class properties (computed/literal, static/instance)
* doc: Update babel-types with ClassProperty.computed
* chore(package): update babylon to v6.11.0
* babel-types: move ClassProperty.computed to be last builder arg
* Fix class inheritance in IE9 & IE10 (T3041)
Internet Explorer 9&10 do not support __proto__ at all, don't have
Object.setPrototypeOf(), but have Object.getPrototypeOf().
Because of this setting the prototype is not possible, which makes the
babelHelpers.inherits() function to set __proto__ although not supported.
Afterwards Object.getPrototypeOf() is used, but this one is not
respecting the "custom" property __proto__ that we set.
The solution is to check for __proto__ first and afterwards fallback to
Object.getPrototypeOf().
* Do the same logic in babel-helper-replace-supers
* Fix tests
* Extract creation of prototype nodes to small helper
