Fix fatal error in WP_User_Query when searching users by URL. Move wp_is_large_network() to wp-includes. fixes #23683 for trunk.

git-svn-id: http://core.svn.wordpress.org/trunk@23664 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Improve punctuation in phpdoc. see #23090.

git-svn-id: http://core.svn.wordpress.org/trunk@23665 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Always respect $echo argument in get_search_form(). props garyc40, kawauso. fixes #16541.

git-svn-id: http://core.svn.wordpress.org/trunk@23666 1a063a9b-81f0-0310-95a4-ce76da25c4cd