Theme Installer: Use 'browse' instead of 'sort' for routes.

see #27055.

Built from https://develop.svn.wordpress.org/trunk@28035


git-svn-id: http://core.svn.wordpress.org/trunk@27865 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Theme Installer: Left/right arrow keys in the overlay.

props adamsilverstein.
see #27521.

Built from https://develop.svn.wordpress.org/trunk@28036


git-svn-id: http://core.svn.wordpress.org/trunk@27866 1a063a9b-81f0-0310-95a4-ce76da25c4cd