Support crossposting password protected posts, too.

git-svn-id: https://plugins.svn.wordpress.org/wp-crosspost/trunk@884780 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update readme, version bump to 0.2.1.

git-svn-id: https://plugins.svn.wordpress.org/wp-crosspost/trunk@884782 b8457f37-d9ea-0310-8a92-e5e31aec5664