Format LV Error as JSON Data - add message

[pollockm]

Currently only get the code and source. Makes for easier system debugging (assuming error files are on the target) if the message is inline with the error report.

Like this:

[tannerblair]

This was omitted for performance reasons. The native error handlers are non-reentrant and have performance issues on RT, so I would like to avoid using them.

[pollockm]

Fair enough. Can it be a toggle option then as to whether it is used? Not having to look up every error code is a godsend when debugging a flaky system.

[tannerblair]

I'm open to it. I agree with the pain point, let me think on the best way to implement it.