bump version to 2.0

git-svn-id: https://plugins.svn.wordpress.org/mp6/trunk@765004 b8457f37-d9ea-0310-8a92-e5e31aec5664
tagging version 2.0

git-svn-id: https://plugins.svn.wordpress.org/mp6/trunk@765005 b8457f37-d9ea-0310-8a92-e5e31aec5664