Changing for the create_exception works

[hazelld]

I think we need to find a more elegant way to set this up, I'm not sold on the way we do it now. One issue I see would be if someone was to do:

create_exception(excep1); create_exception(execp2);

Maybe we keep an internal lists of the used IDs and what they reference? That we it also adds the ability to throw that custom exception from inside a function in the try block, like:

func1() {
create_exception(e);
try {
func2();
} catch (e) { ... }
}

func2() {
throw(e);
}

I'll start working on something like this on another branch and see what I can come up with.