cv2.findContours fix

[sumanmichael]

in the 135 line changed this

_, contours, hierarchy = cv2.findContours(work, cv2.RETR_CCOMP, cv2.CHAIN_APPROX_NONE)

to this

contours, hierarchy = cv2.findContours(work, cv2.RETR_CCOMP, cv2.CHAIN_APPROX_NONE)

it's because in a previous version of opencv that function used to return 3 values, now it returns just 2 values