Showing issue of illegal node names with possible underscore-replacement. (Will currently assterted to an Exception).

[mdaehnert]

This UnitTest shows the named problem.

Some more hints

• Discussion: https://github.com/douglascrockford/JSON-java/pull/123
• Pull request for solution: https://github.com/douglascrockford/JSON-java/pull/138
• Commit: https://github.com/JaXt0r/JSON-java/commit/554e9966089b007acbb14763feb2946c92aa0c0e