A Multicenter, Randomized, Investigator-Blinded Study (MODEC) Comparing the Cleansing Quality and the Observed Lesion Detection Rate of Two Bowel Preparations: 2L Polyethylene Glycol with Electrolytes + Ascorbate Components (PEG+ASC) and Sodium Picosulfate/Magnesium Citrate (NaPic/MgCit)