todo

这是用matlab对segy数据进行处理

TODO LIST 

ReadSegy 
* Honour FixedTraceLength in SegyHeader.
* When both 'trange' and 'minmax' header value are selected, then the
  time series returned is wrong....
* EBCDIC Headers cannot currently be read, only ASCII
* TraceHeaderInfo return wrong time axis ....
* ReadSegyFast : only big endian style for now. Looks similar to ReadSegy. 
                 Maybe it should be integrated in ReadSegy
	         Maybe a ReadSegyBlock should be implemented, that 
                 simple reads all the data in the file in one fread statements and then 
                 uses reshape without the header values. This should be very fast.

* ReadSegy : Adjust SegyHeader when reading inly a part of a SEGY file !!

* wiggle : make it stable.