QUrl: add fileName() method. Complements QUrl::RemoveFilename.

Change-Id: Ieda43364214c3b7aee43040e176e29ad48c14271
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
QUrl: let StripTrailingSlash remove multiple trailing slashes

Change-Id: Ic4c8f70bb729630d9110ed6766dd9e40f9ab4d80
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>