Go library with improved reflect.DeepEqual

 Most of the code is copied from Go reflect package with slight
 modifications.
 .
 Differences from reflect.DeepEqual:
   * If compared value implements .Equal(valueOfSameType) bool method then
     it will be called instead of comparing values as is.
   * If called Equal method will panics then whole DeepEqual will panics too.
 .
 This means you can use this DeepEqual method to correctly compare types
 like time.Time or decimal.Decimal, without taking in account unimportant
 differences (like time zone or exponent).