Merge branch 'stable-3.1'

* stable-3.1:
  Bazel: Remove unused java_library import
  Bump Bazel version to 2.0.0
  Upgrade bazlets to latest stable-2.16 to build with 2.16.15 API
  Upgrade bazlets to latest stable-2.16 to build with 2.16.14 API
  Upgrade gitiles-servlet to 0.2-7.1
  Upgrade bazlets to latest stable-2.16 to build with 2.16.13 API
  Upgrade bazlets to latest stable-2.16
  Upgrade bazlets to latest stable-2.15 to build with 2.15.18 API
  Bazel: Migrate workspace status script to python
  Upgrade bazlets to latest stable-2.15
  Upgrade bazlets to latest stable-2.14
  Upgrade bazlets to latest stable-2.16
  Upgrade bazlets to latest stable-2.15
  Upgrade bazlets to latest stable-2.14
  Bump Bazel version to 1.1.0
  Replace bazel-genfiles with bazel-bin in documentation

Change-Id: I646b195ea8623873470589656ff2656329cdf03b