Remove ‘ob_clean’ function from renderOutputHeaders method
Remove ‘ob_clean’ function from renderOutputHeaders method

It was unnecessary and was causing errors in images in some environments. Sorts symphonycms/jit_image_manipulation#67

DeuxHuitHuit/jit_image_manipulation,DavidOliver/jit_image_manipulation,avanteweb/jit_image_manipulation,DavidOliver/jit_image_manipulation,avanteweb/jit_image_manipulation,DeuxHuitHuit/jit_image_manipulation