Merge branch 'stable-3.0' into stable-3.1

* stable-3.0:
  Update codemirror-editor
  Update git submodules
  Bazel: Fix plugin api javadoc generation
  Update git submodules
  Update git submodules
  Update git submodules
  Update git submodules
  ElasticContainer: Upgrade V6_8 to elasticsearch 6.8.7
  Add new prolog fact to documentation
  Add prolog predicate to determine number of parents

Change-Id: Ic8b28c079a74483242f9880839f6062ee02cabfa
tree: dd040955048625c857c3f4d890fa49411774f63a
  1. java/
  2. javatests/