Fix URL detection corner cases.
Remove unused cookiejar NetworkManager, fix parenting.

Before, the QWebPage got passed to the QNetworkAccessManager as cookiejar,
causing no parent to be set. Now, the QWebPage actually owns the
QNetworkAccessManager.
Shut down NetworkManager before deleting WebPage.

Now that the QWebPage actually is a parent of the QNetworkAccessManager, first
setting the page to None and then deleting the QNetworkAccessManager will get
us a RuntimeError because the underlying C++ object is already gone.
urlutils: Strip URL before testing.
Strip spaces in url string correctly.
Handle IPv6 literals correctly.
Add fancy URL to tests.
Rename tests to reflect renamed modules.
More HACKING docs.