Removed several PHP warnings. Updated widget to work with WordPress 4.0 customizer. Added plugin icons.

git-svn-id: https://plugins.svn.wordpress.org/organized-docs/trunk@971990 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update changelog.

git-svn-id: https://plugins.svn.wordpress.org/organized-docs/trunk@971994 b8457f37-d9ea-0310-8a92-e5e31aec5664