Issue #3080: zipimport has a full unicode suppport

- Use Unicode for module paths and names, self->archive and self->prefix
 - Format module names and paths use %R instead of '%U' to escape surrogate
   characters (PEP 383)
 - Use PyImport_ExecCodeModuleObject() instead of PyImport_ExecCodeModuleEx()
 - Use PyImport_AddModuleObject() instead of PyImport_AddModule()