Tagging release 1.2.1

git-svn-id: https://plugins.svn.wordpress.org/youtube-comments/tags/1.2.1@804417 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fix HTTP 500 for videos with disabled comments
Fix redirection problems
Fix commenting
Implement login popup
Show "Your comment has been posted and will appear soon" message
Show "Visit YouTube to comment" only when direct commenting is disabled
Add support for wpzoom_post_embed_code field
Edit styles