Bug 1033666 - Add URL for website field in Profile.

@tessie You're going to hate me for this, but I just noticed one other thing. If the person has not set a Personal URL then on their profile this appears as just "Personal URL:" with no value. That's kind of ugly. Can you please wrap this in a `{% if }` so that it only displays if the user has set a value for `personal_url`?

Thanks!