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: I9f8b2222292e489d903d543b26b46e681488e4e0