Added features:

• (#108) The _ field is always ignored when comparing a struct.
• (#109) The naming rules for cmp.Transformer is relaxed and clearly specified.
• (#82) cmpopts.AcyclicTransformer makes it easier to write a transformer that avoids infinite recursion when the output type contains the input type.
• (#126) cmpopts.IgnoreSliceElements and cmpopts.IgnoreMapEntries provide the ability to ignore specific slice elements or map entries.
• (#123) cmp.Reporter provides users the ability to add custom difference reporters.
• (#119) cmp.PathStep.Values provide the current reflect.Value for the x and y arguments at that given path step.

Bug fixes:

• (#87) Fixed proper comparing of slices where one is a sub-slice of the other.

Reporter changes:

• (#124) The cmp.Diff output has been completely re-written to provide a unified diff of the two Go objects as a literal in pseudo-Go syntax (example).
• (#131) The default reporter has built-in heuristics to detect whether a string or a byte-slice looks like binary data or human readable text, and can provide more humanly readable differences in certain use-cases. For example, a string may be detecting as containing multiple lines of text, for which it will print the difference based on the lines.