Make QUuid support returning the UUID without curly braces

The DCE standard does not use curly braces ('

') for representing an UUID as a string, so it would be nice if QUuid supported returning a string representation of the UUID without curly braces as well. Currently, the QUuid::toString() function returns the UUID enclosed with curly braces.

Workaround: Remove the curly braces manually with the QString functions (QString::remove(), for instance).