Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Upgrade bazlets to latest stable-2.16
  Upgrade bazlets to latest stable-2.15
  Bump required bazel version to 1.0.0rc2
  Upgrade bazlets to latest stable-2.14

Change-Id: I6ad2cc6a0f126514771d1774e3a671122a6616e5