subarray Function
Purpose:
Returns a new array that is a subset of the given array
Syntax:
newarray = subarray(input,position1,position2)
Comments:
position 2 must be greater than position 1
Using this routine is much faster and easier to use than copying array items yourself in a loop
Example:
b2 = subarray(b1,aud.mark1,aud.mark2-aud.mark1)