Show comments when viewing a page in Manage Pages

[ryan]

When displaying only one post, Manage Posts shows that post's comments. Sample url: edit.php?p=56&c=1

We need to do the same for edit-pages.php.

[ryan]

(In [7077]) fix new-fangled multi widgets. Props mdawaffe. see #6022

[ryan]

(In [7078]) Show comments when viewing a page in Manage Pages. fixes #6022

[ryan]

(In [7079]) Add edit comments js to edit-pages when viewing a page's comments. see #6022