A CROSS-OVER STUDY TO EVALUATE LUNG FUNCTION RESPONSE AFTER TREATMENT WITH UMECLIDINIUM (UMEC) 62.5 MICROGRAMS (MCG), VILANTEROL (VI) 25 MCG, AND UMECLIDINIUM/VILANTEROL (UMEC/VI) 62.5/25 MCG ONCE-DAILY IN SUBJECTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD):