chore: update to angular 4 final & fix animations

Fix mgechev#1880

Merge branch 'master' of https://github.com/mgechev/angular-seed

* 'master' of https://github.com/mgechev/angular-seed:
  Specify ENABLE_SCSS setting via environment variable (mgechev#1603)