XMLRPC Comments API

[ryan]

Add API to XMLPRC for retrieving and managing comments.

There's been some discussion about this on the wp-xmlrpc list:  http://comox.textdrive.com/pipermail/wp-xmlrpc/

Incomplete and untested preview

Drop separate method for setting comment status. Flesh out editComment.

Add get_comments(). Register methods. Deprecate some old stuff.

All methods tested except newComment. It needs some more work.

Allow fetching comments for a particular post

getComments() accepts optional status and post_id. A separate getPostComments() has been suggested. It'd probably just be an alias to getComments() with different argument passing if we added it.

newComment() needs a little more work. All other methods have had basic testing and are hopefully complete.

Working newComment

In 7446.6 all methods are completed and tested. I left support for unregistered commenting out of newComments for now.

Handle anonymous comments

Add offset and number support to getComments

Couple small corrections

wp-xmlrpc list conversation:

 http://comox.textdrive.com/pipermail/wp-xmlrpc/2008-August/000258.html

(In [8543]) XML-RPC comments API. see #7446

When editing a comment in moderation,  http://trac.wordpress.org/browser/trunk/wp-includes/comment.php?rev=8543#L863 is causing the comment to be be approved with any changes to the Approval Status.

(In [8622]) comment_approved can be zero, so check with isset instead of empty. fixes #7446

(In [8698]) Typo fix. Props josephscott. see #7446