Code review comment for lp:~sense/lernid/browserbuttons-sensitivity

This branch makes the browser toolbar and the stop and reload buttons grey out (and in) when they should by listening to the 'hide', 'net-start', 'net-stop' and 'show' signals of self.browser.
Now you can't press Reload when a page is being loaded and you can only press Stop when something actually is being loaded.

If self.browser is being hidden the toolbar is made completely insensitive.

The browser toolbar and the stop button have been set to insensitive by default in the .ui files.