URLs must contain at least one "."

We started prepending http:// to the start of URL values so the user
didn’t have to. This left a hole in our validation where “something”
would become “http://something” and pass validation checks.

* Check host contains at least one period, mostly to prevent accidents
Merge pull request #256 from alphagov/new-urls-must-contain-a-dot

URL hosts must contain at least one "."