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

see #27055.


git-svn-id: https://develop.svn.wordpress.org/trunk@28035 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Left/right arrow keys in the overlay.

props adamsilverstein.
see #27521.


git-svn-id: https://develop.svn.wordpress.org/trunk@28036 602fd350-edb4-49c9-b593-d223f7449a82