message: Update documentation to mention objects with unsorted index table.
diff: @@ -48,7 +48,14 @@ reference, for arrays and objects see below for details:
  attribute name, 4-byte bytelen and # subvals
  - 0x0e : object with 8-byte index table offsets, sorted by
  attribute name, 8-byte bytelen and # subvals
  - - 0x0f-0x12 : unused
  + - 0x0f : object with 1-byte index table offsets, not sorted by
  + attribute name, 1-byte bytelen and # subvals
  + - 0x10 : object with 2-byte index table offsets, not sorted by
  + attribute name, 2-byte bytelen and # subvals
  + - 0x11 : object with 4-byte index table offsets, not sorted by
  + attribute name, 4-byte bytelen and # subvals
  + - 0x12 : object with 8-byte index table offsets, not sorted by
  + attribute name, 8-byte bytelen and # subvals
  - 0x13 : compact array, no index table
  - 0x14 : compact object, no index table
  - 0x15-0x16 : reserved
  