Range := Object clone.
A range object is a collection parameterized by a
start position, an end position, and a step value. Note that all
ranges are half-open intervals, so start is inclusive and end
exclusive.
Range toString := "Range".
Range start.Returns the start value for the range.
Range finish.Returns the ending value for the range.
Range step.Returns the step value for the range.
Range iterator.Returns a RangeIterator representing
this collection as an iterator.
Range do (block).Equivalent to self visit (block).
Range make (a, b, d).Constructs a range which starts at a, has a finishing value of b,
and steps by d. All three arguments shall be numbers, with d
nonzero.