Package for equality of Go values

This package is intended to be a more powerful and safer alternative to reflect.DeepEqual for comparing whether two values are semantically equal. The primary features of cmp are when the default behavior of equality does not suit the needs of the test, custom equality functions can override the equality operation. For example, an equality function may report floats as equal so long as they are within some tolerance of each other. Types that have an Equal method may use that method to determine equality. This allows package authors to determine the equality operation for the types that they define. If no custom equality functions are used and no Equal method is defined, equality is determined by recursively comparing the primitive kinds on both values, much like reflect.DeepEqual. Unlike reflect.DeepEqual, unexported fields are not compared by default; they result in panics unless suppressed by using an Ignore option.