- Added a REDIM statement to dynamically redimension an array at run-time.
   To use it you must declare the array in advance with the number of
   subscripts desired.  This allows the compiler to perform it's standard
   error checking on subscripts.  For example:

    STRING s(1,1,1)
    REDIM s,5,5,5
    LET s(4,4,4) = "Hello, World!"
    PRINTLN s(4,4,4)

   If an attempt is made to redimension an array with a different number
   of dimensions, an error or warning (as appropriate) will be generated.