[INTERPRETER] * NEW: Classes passed to 'gbx3 -T' that are not test modules are silently ignored.
[INTERPRETER] * NEW: Redesign the interface between the interpreter and 'gb.test'.
[INTERPRETER] * NEW: Now '-T' option with no argument calls Test._List() method. * NEW: If '-T' gets an argument, the Test._Run() method is used. * NEW: If '-T' argument is '*', then the Test._RunAll() method is called.