Fix #46 and bug in fragment.e4xmi
As it turns out, the scope can't be captured because it is indeed not contained anywhere where we can extract it, as far as I an see at least.
As for the issues complaint that 'the scope should at least be null instead of "null" in these cases', that is already the case. The event's toString method just doesn't do a very good job of showing that, so it has been adjusted to display null instead of 'null'.
Additionally, the fragment.e4xmi is apparently not allowed to contain ampersands (&), so those have been replaced by the word "and".
Closes #46