Separate data type for segmented arrays
Separate data type for segmented arrays

  - nested UArrs and UArrs of sums no longer supported
  - new data types SUArr and MSUArr for segmented arrays
  - at the moment, only one level of nesting is supported
    (but support for multiple nesting levels has been at least somewhat
    broken in the previous version anyway)

mainland/dph,mainland/dph,mainland/dph