Edited Feature: Throw specific script exception by host [43]

Hi,

Would it be possible to add a custom exception, so that when it is thrown by host it throws a script exception of the specified type and message.

For example, in host code:

```
throw new CustomScriptException("RangeError", "custom message");
```

will cause script to execute:

```
throw new RangeError('custom message');
```

Specifically, for the example above I need the exception to be instanceof RangeError.

Thanks again in advance,
Ron