Fork of stretchr/testify/assert that uses FailNow()

 This is a fork of stretchr's assertion library that does two things:
 .
 1. It makes spotting differences in equality much easier. It uses
    github.com/alecthomas/repr and github.com/sergi/go-diff/diffmatchpatch
    to display structural differences in colour.
 2. Aborts tests on first assertion failure (the same behaviour as
    stretchr/testify/require).