Tagging 2.0.0, requires LP 2.0.0 or greater

git-svn-id: https://plugins.svn.wordpress.org/leaky-paywall-article-countdown-nag/trunk@958038 b8457f37-d9ea-0310-8a92-e5e31aec5664
Tagging 2.0.0 and fixing readme.txt

git-svn-id: https://plugins.svn.wordpress.org/leaky-paywall-article-countdown-nag/trunk@958041 b8457f37-d9ea-0310-8a92-e5e31aec5664