update to 0.18.1

git-svn-id: https://plugins.svn.wordpress.org/timber-library/trunk@913289 b8457f37-d9ea-0310-8a92-e5e31aec5664
update to 0.18.1

git-svn-id: https://plugins.svn.wordpress.org/timber-library/trunk@913291 b8457f37-d9ea-0310-8a92-e5e31aec5664
update to 0.18.1

git-svn-id: https://plugins.svn.wordpress.org/timber-library/trunk@913293 b8457f37-d9ea-0310-8a92-e5e31aec5664