Why doesn't the normal way of settings, Add-ons, and then under search providers add Google and make it the default work? It works for me except at work, if I happen to be on my crappy Lenovo, when the admin policy seems to wipe out the default setting every 10 minutes.
Beyond me, i'm no programmer. Doing that works exactly as would be expected, until you get to the page where you chose your new search provider, and clicking the button does nothing. Right clicking and selecting open does nothing. Really wouldn't surprise me if it is intentional. MS have a raging hard-on over the idea of making people like bing. Well I don't, it can't return a worthwhile search result worth a damn.