3 minor diagram errors in module 7

[Rudel]

As I was going through all the exercises for module 7 today, I found 3 diagram errors. None of them should affect the solutions (I hope).

In diagram 17, there should be a White pawn on a3.
In diagram 47, there should be a White pawn on a4.
In diagram 60, there should be a Black pawn on a5.