Merge branch 'stable-2.13'

* stable-2.13:
  Build with API version 2.13
  Fix buck build, remove java_test.source_under_test

Change-Id: I6cb12c9f788a0590dd22198585a66c2b75f98daf
tree: 9e07e5638f679920efdda0e26cf570a54e426eb0
  1. .buckconfig
  2. .gitignore
  3. BUCK
  4. lib/
  5. src/