Changing test failure to be ignored in browsers with buggy innerHTML implementation

As discussed in #962, I changed the test failure in App to use feature detection to determine if the browser has a buggy innerHTML implementation.  This will at least allow Android 2.3.x browsers and < IE9 to ignore the test, so the error doesn't come up again.

I'll start writing the documentation on how to better format the HTML response so that Pjax will work, even on those browsers.