message: docs: add changelog for 4.0.0
diff: +<a name="4.0.0"></a>
  +# [4.0.0](https://github.com/angular/angular/compare/4.0.0-rc.6...4.0.0) (2017-03-23)
  +
  +
  +### Bug Fixes
  +
  +* **compiler:** assume queries with no matches as static ([#15429](https://github.com/angular/angular/issues/15429)) ([c8ab5cb](https://github.com/angular/angular/commit/c8ab5cb)), closes [#15417](https://github.com/angular/angular/issues/15417)
  +* **compiler:** correctly handle when `toString` is exported ([#15430](https://github.com/angular/angular/issues/15430)) ([0dda01e](https://github.com/angular/angular/commit/0dda01e)), closes [#15420](https://github.com/angular/angular/issues/15420)
  +* **platform-browser:** setAttribute should work with xmlns namespace ([#14874](https://github.com/angular/angular/issues/14874)) ([92084f2](https://github.com/angular/angular/commit/92084f2)), closes [#14865](https://github.com/angular/angular/issues/14865)
  +* **router:** should pass new data to Observable when query params change ([#15387](https://github.com/angular/angular/issues/15387)) ([08f2f08](https://github.com/angular/angular/commit/08f2f08)), closes [#15290](https://github.com/angular/angular/issues/15290)
  +* prevent strictNullChecks support until [#15432](https://github.com/angular/angular/issues/15432) is fixed ([#15434](https://github.com/angular/angular/issues/15434)) ([b800a0c](https://github.com/angular/angular/commit/b800a0c))
  +
  +
  +
  <a name="4.0.0-rc.6"></a>
  # [4.0.0-rc.6](https://github.com/angular/angular/compare/4.0.0-rc.5...4.0.0-rc.6) (2017-03-23)
  