Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  Upgrade bazlets to latest stable-2.15 to build with 2.15.9 API
  Upgrade bazlets to latest stable-2.14 to build with 2.14.18 API
  Do not fetch commit message for ref deletions
  Revert "Fix ref updated event on change deletion"
  Bazel: Include eclipse-out directory in .bazelignore
  Add explanatory comment to empty BUILD file(s)
  Upgrade bazlets to latest stable-2.15 to build with 2.15.7 API
  Upgrade bazlets to latest stable-2.14 to build with 2.14.17 API
  Upgrade bazlets to latest stable-2.15 to build with 2.15.6 API
  WORKSPACE: Make commented out local_path line spaces indent consistent
  Upgrade bazlets to latest stable-2.14 to build with 2.14.16 API
  Migrate `tools/bazel.rc` to `.bazelrc`
  Update build documentation to link to dev-bazel instead of dev-buck
  Align Eclipse compiler settings with core Gerrit's
  Upgrade bazlets to latest stable-2.15 to build with 2.15.5 API
  bazlets: Replace native.git_repository with skylark rule
  Upgrade bazlets to latest stable-2.14 to build with 2.14.15 API
  Add eclipse-out to .gitignore
  Format all build files with buildifier 0.15.0
  Update bazlets to latest revision on stable-2.15
  Remove commented-out code
  Format BUILD files with buildifier 0.12.0
  Format Java files with google-java-format 1.6
  Update bazlets to latest revision on stable-2.14

Change-Id: I49f57257660bcd01bc65a06a0af802980a4476fe