In unified drivers, migrate code out of MyDriver::process

Process should be factored away but it is part of the legacy interface so we can't get rid of it yet. Utimately an xmlNodePtr should not be an input argument to any method in any driver.

We want to move toward driver objects that a created as valid objects one per QMC Section and which have known data outputs that go to the constructor of the next driver.

When writing new drivers do as little as possible in process, if you do need information in the XML if it is not already parsed in a input object, make a new input object.