Removing more dead code from the UI

Removing more dead code from the UI.  Tested manually and with "grunt test"
We no longer change the icon at all.  If you search for callers of _setProxying, you will see it was only called with a value of false, i.e. the user started out with the non-proxying icon, then when the start proxying the icon no longer changes (I believe after the polymer rewrite), then when they stop proxying the icon is set again to the non-proxying icon (meaning nothing changed)..  So I'm just removing no-op code here.  We will revisit icons and other notifications once we have our new UX design in about a month