Making the "don't publish to facebook" checkbox sticky

IF auto-post is on AND you check "don't publish to facebook", then you hit save or schedule the post for the future, the setting is forgotten and the post will publish to facebook.

I modified the code in my local copy to save the skip setting in the wdfb_scheduled_publish post_meta. I've attached the two affected files and screencap of the diffs. If you think this code is good, I'd really appreciate you merging it into the final code so I don't have to keep modifying this in my local copy.

Seperately, you'll notice I changed "post to facebook with a different title" to "post to facebook with a custom message", our writers were confused by the old message since that makes it sould like the blog post article is changing, which it is not since facebook will show the blog post title below.