ROADMAP update.
Add ops and REPR funcs for natively typed arrays.
Teach VMArray about int/num/str storage.

There may be more beautiful solutions, but this one will should Just
Work.
Create BOOTIntArray etc.; implement list_i/n/s.

nqp::list_i() was the pressing one for the regex engine, but did the
rest while I was at it.
Uncomment various key parts of Cursor.