Order an order of elements with a numerical index

Inherits from: Object : Collection : SequenceableCollection

Keeps elements in an order and allows to put them at arbitrary slots 

without having to allocate a large array. 

see also: SparseArray

Note: put and at are slower than in IdentityDictionary / PriorityQueue, do is faster.

*new(size)

create a new order.

//  example

g = Order.new;

g.put(7, 100); // put a value (100) at index 7

g.clear; // empty

*newFromIndices(array, indices)

create a new order from given items and indices

*doRange(function, from to)

iterate over a range of the order's items.

// example

a = Order.new;

a[0] = \z;

a[0] = \y;

a[5] = \five;

a[4] = \four;

a[0] = \z;

a[5] = \five;

a[4] = \four;

a.indices;

a[9] = 100;

a.indices;