The output of FunctionPrototype::to_string is now more in line
with the output in Firefox. The builtin constructors have been
extended to include their function name in the output.
This patch adds instance, constructor and prototype classes for:
- EvalError
- InternalError
- RangeError
- ReferenceError
- SyntaxError
- TypeError
- URIError
Enumerator macros are used to reduce the amount of typing. :^)