Merge branch 'stable-2.16'

* stable-2.16:
  Upgrade bazlets to latest stable-2.16 to build with 2.16.6 API
  Add the standard LICENSE file
  Upgrade bazlets to latest stable-2.15 to build with 2.15.11 API

Change-Id: Ie49b1eabeeb96c5f18a74a30f53410d558f5e3a1