Removing license.txt now that I have a website link in the readme

git-svn-id: https://plugins.svn.wordpress.org/read-later-buttons/trunk@808871 b8457f37-d9ea-0310-8a92-e5e31aec5664
Use the checked() function to set checkbox "checked" status

git-svn-id: https://plugins.svn.wordpress.org/read-later-buttons/trunk@808872 b8457f37-d9ea-0310-8a92-e5e31aec5664