Minor API change proposal for overloaded verifyAll functions

[ragunathjawahar]

The following overloaded function has a parameter named f1. It is unclear what this function does and requires a bit of guess work. Can we rename it to formatter?

Now

public static <T> void verifyAll(String header, Iterable<T> array, Function1<T, String> f1)

After

public static <T> void verifyAll(String header, Iterable<T> array, Function1<T, String> formatter)

This change would still maintain binary compatibility backwards. I can raise a PR if necessary. Thanks.