Handle segy (SU) and seg-2 files in go.

Read and write segy(SU) files. SU files are like seg-y Rev 1, but without the 3200 byte EBCDIC or 400 byte binary header.

Read seg-2 files.

https://github.com/JohnWStockwellJr/SeisUnix https://cwp.mines.edu/software

SEG-Y: Barry,K. M., Cavers,D. A., and Kneale,C. W., 1975,Recommended standards for digital tape formats: Geophysics 40. 344-352.

SEG-2: Recommended standard for seismic (/radar) data files in the personal computer environment. Subcommittee of the SEG Engineering and Groundwater Geophysics Committee, S. E. Pullan, Chairman