ref(Vagrantfile): align with upstream coreos-vagrant

See "deis" fork at https://github.com/deis/coreos-vagrant
Merge pull request #1881 from mboersma/update-coreos-vagrant

ref(Vagrantfile): align with upstream coreos-vagrant
ref(tests): move test-nightly to test-latest
Merge pull request #1965 from gabrtv/test-latest

ref(tests): move test-nightly to test-latest
feat(router): build an image without development libraries to reduce the size.
fix(router): keep changes from the master.
fix(router): merge.
Merge branch 'reduce_router_image_size' of https://github.com/aledbf/deis into reduce_router_image_size

* 'reduce_router_image_size' of https://github.com/aledbf/deis:
  fix(router): merge.
  fix(router): keep changes from the master.
  feat(router): build an image without development libraries to reduce the size.