Merge branch 'master' into svn

git-svn-id: https://plugins.svn.wordpress.org/papercite/trunk@1001161 b8457f37-d9ea-0310-8a92-e5e31aec5664
Bump to 0.5.15

git-svn-id: https://plugins.svn.wordpress.org/papercite/trunk@1001163 b8457f37-d9ea-0310-8a92-e5e31aec5664