infinty loop in motion_blur

[Remosy]

Hi, i found a small issue in 'Automold.py', line638 makes my code loop forever from 640(my image shape[1]) to infinity negative number. I fix this by adding one more condition to make sure it will stop before negative numbers coming.

original code:
while(i<=imshape[1]):

my solution:
while(i<=imshape[1] and i>=0):

P.S: awesome work!! it's really helpful! Thank you UjjwalSaxena