Add support for go funcs which return multiple values by returning them as an array.
In the future this can be used along side destructuring assignment to provide a nice way to deal with multiple value returns e.g.
[val, err] = MyGoFunc()
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
This fixes#68
Some changes over the original patch, removing references to utf8string.String:
* (better) This removes a dependency on a non-standard (though solid) package
* (better) utf8string.String has mutable parts
* (worse) utf8string.String has a smarter consecutive access approach (by
remembering where the last access was)
* (?) _stringWide allocates a []rune if charAt or charCodeAt access is needed (though
it will only do this once for the string object)
* Streamline what we get from "otto/parser"
* Get rid of some "otto/parser" cruft
* FunctionExpression => FunctionLiteral
* The debugger statement (debugger) should do nothing (not panic)
* Fix aspects of function expression call evaluation
* The "reflect" package is willing to expose unexported fields in structs (a little suprising).
* Skip unexported fields when enumerating or trying to access (pretend they don't exist).
* Allow structs that implement json.Marshaler to work as expected in a JSON.stringify call.
If we let the runtime try to access unexported fields, it'll cause a panic.
This fixes#64
* 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
