[Avatars] Calculate 'sane' hue precissions
We used to get the numeric value of the entrire md5 string which is a 128bit integer. We would then devide this by the maxval of a 128bit int. There is no need for such huge computations. As we just require a value between 0 and 255. Thus using two 16 bit values is more than enough to get the precision we need. By just taking the MSB we get nearly identical results.