Comments can be threaded. Now your query can be threaded too! Bonus: it's
not totally insane.
* The new `$hierarchical` parameter for `WP_Comment_Query` accepts three values:
* `false` - Default value, and equivalent to current behavior. No descendants are fetched for matched comments.
* `'flat'` - `WP_Comment_Query` will fetch the descendant tree for each comment matched by the query paramaters, and append them to the flat array of comments returned. Use this when you have a separate routine for constructing the tree - for example, when passing a list of comments to a `Walker` object.
* `'threaded'` - `WP_Comment_Query` will fetch the descendant tree for each comment, and return it in a tree structure located in the `children` property of the `WP_Comment` objects.
* `WP_Comment` now has a few utility methods for fetching the descendant tree (`get_children()`), fetching a single direct descendant comment (`get_child()`), and adding anothing `WP_Comment` object as a direct descendant (`add_child()`). Note that `add_child()` only modifies the comment object - it does not touch the database.
Props boonebgorges, wonderboymusic.
See #8071.
git-svn-id: https://develop.svn.wordpress.org/trunk@34546 602fd350-edb4-49c9-b593-d223f7449a82
e1b44f5203