Method of reporting is cumbersome

[chevinbrown]

We love this library, but there's one thing that is really irking. The way test failures are reported...

Given large assertions (we have large json objects), when a failure occurs within a large block, the error reported doesn't specify what token, or what line.

I've wanted to provide a PR, but we've been quite busy and haven't had a moment to contribute to OSS.

Do you have any thoughts on this?