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: Iad2b1a7ade66feda10f7c61b73f660240b662a56