Phase 2, Randomized, Open-Label Clinical Trials of the Efficacy and Safety of Grazoprevir and MK-3682 (NS5B Polymerase Inhibitor) with Either Elbasvir or MK-8408 (NS5A Inhibitor) in Patients with Chronic HCV GT1, 2 or 3 Infection (Part A of C-CREST-1 & 2)