Update README.md

In Novice.4, I think you want the `./` operator, to make it clear that you're doing element-wise division. (It works either way.)

In Novice.6, you can get the same effect using a list (well, a matrix) comprehension. The comprehension version seems more readable to me.

In Novice.8, there is a distinction in Julia between `sort` and `sort!`. `sort` copies its argument before editing it, then returns the sorted copy (leaving the original unchanged. `sort!` sorts the array in-place, so there's no copying of the entire array. This distinction becomes important when running functions over large data sets (if they take up > half your RAM) or when doing performance tuning (copying/allocation takes time).
(Your answer was correct; I just felt this question became more useful if you look at both sorts.)