[MOD] blogs: do not display a dropdown list of blogs to post to (in tiki-blog_post.php) if there is only one blog where the user can post or if the user came from a specific blog + when writing a new post (i.e. not editing an existing one), the title is 'Post' instead of 'Edit Post'
[FIX] blogs: do not add a hidden input field for 'blogId' when it can be selected in a list by the user