Modifying Item core methods

Item.create renamed Item.new.
A more suitable name as it creates but also call constructor

Item.proto(object)
A = Item('a');
a = Item.new(A);
Item.proto(a) == A; -> true;

Item.is(object, subobject)
B = Item.extend(A, 'b');
b = Item.new(B);
Item.is(A, b); -> true
Item.is(B, b); -> true