Update to 0.19.0

git-svn-id: https://plugins.svn.wordpress.org/timber-library/trunk@918804 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update to 0.19.0

git-svn-id: https://plugins.svn.wordpress.org/timber-library/trunk@918805 b8457f37-d9ea-0310-8a92-e5e31aec5664