Incorrect URLs Cause Crashes

[fennifith]

The GitHub API appears not to verify that URLs input into the 'blog' field are actually URLs, so if a url that doesn't start with either http:// or http:// is provided then Attribouter crashes whenever one is clicked (since it just throws the value directly into the ACTION_VIEW data without checking that it's valid). Ideally, it should be validated before the link is even created so that even if the URL is invalid for some other reason, it still doesn't cause an error.