QUrl should use trimmed url

When an URL contains leading whitespace and an QUrl is created from that it results in empty url.

QUrl myUrl(" http://www.google.com");
qDebug() << "My url: " << myUrl.toString();

->
$ My url:  ""

Steps to reproduce:
1. Run attached test app

Expected:
Url is printed.

Actual:
Empty string is printed.