same as getTypeCode() in ControlHeader, just a convenience method as the type code is called a
Data header/quality indicator in the seed documentation for data header.
Instantiate an object of this class and read an FSDH byte stream into it,
parsing the contents into the instance variables of this object, which
represent the individual FSDH fields.
Note, first 8 bytes are assumed to already have been read.
Order the result by time or magnitude with the following possibilities: time: order by origin descending time time-asc : order by origin ascending time magnitude: order by descending magnitude magnitude-asc : order by ascending magnitude