prepare new release and assets

git-svn-id: https://plugins.svn.wordpress.org/youtube-channel/trunk@858854 b8457f37-d9ea-0310-8a92-e5e31aec5664
release 2.0.0

git-svn-id: https://plugins.svn.wordpress.org/youtube-channel/trunk@858856 b8457f37-d9ea-0310-8a92-e5e31aec5664
fix done TODO

git-svn-id: https://plugins.svn.wordpress.org/youtube-channel/trunk@858858 b8457f37-d9ea-0310-8a92-e5e31aec5664