MutableList:

document growth of mutable lists

point out the need to be careful not to convert an order n algorithm into an order n^2 algorithm!

mention hashtables as an alternative

    i31 : t = new MutableList from {};

    i32 : t#4 = e;

    i34 : peek t

    o34 = MutableList{null, null, null, null, e}

document the use of mutable hash tables as push-only stacks:

    i35 : x = new MutableHashTable ;

    i36 : x##x= a;

    i37 : x##x= b;

    i38 : x##x= c;

    i39 : values x

    o39 = {a, b, c}

    o39 : List
