Merge branch 'stable-2.15' into stable-2.16
* stable-2.15:
Upgrade bazlets to latest stable-2.15 to build with 2.15.10 API
Automatically format BUILD file with buildifier lint mode
Upgrade bazlets to latest stable-2.15 to build with 2.15.9 API
Upgrade bazlets to latest stable-2.15 to build with 2.15.8 API
Upgrade bazlets to latest stable-2.14 to build with 2.14.18 API
Bazel: Include eclipse-out directory in .bazelignore
Add explanatory comment to empty BUILD file(s)
Change-Id: Iac505bbea7e769ac50c4fa578af6d78f89c15974