Previously, it was a publically accessible but invalid value (valueEmpty).
* Deprecate internal use of UndefinedValue(), NullValue(), FalseValue(), TrueValue()
* Guard against Empty, Result, Reference values from escaping the package
* Faster, more straightforward, etc.
* More advanced object literals (get ..., set ...)
* More tests using JavaScript from the wild (http://cdnjs.com/)
Basically, the Go runtime sees the gelcap shell of the exception,
which dissolves (payload is set to nil) once we catch the error.
This prevents the Go runtime from hanging onto a heavy object for the
panic log (or whatever it is doing with the panic value).
This fixes#59
