Only run cfpf_format_auto_title_post() if the post title does not alread...

...y exist. This keeps the_title() from being overwritten.

I recently used this plugin for an existing blog and converted some old posts to quote post format. It was then decided to keep the_title() in place as it was before. All the posts that were converted with this plugin required editing to set the_title() back to what it was before.

With this change existing posts will not have the_title() overwritten. New posts with have the_title() set.