Show the value in text field even if it is numerical zero value.

Now, numerical zero value is not showed in text input field,

Like so;
http://gyazo.com/e21f36416cd7198f3e500621cf469c2f

So I fixed it to show zero value in text box,
http://gyazo.com/64125a89a5841b4f21c0b0b9be50a410

Please review and merge it.