* Introduce portable, endian-clean structures using shifts and masks instead of bitfields
* Modernize SCSIExecute with RAII and exceptions
* Convert SP-IN calls to use the new portable SCSI structures and functions
* Convert SP-OUT code to use the new portable SCSI structures and functions
* Delete bitfield-based code and remove runtime endian check
Closes: https://github.com/scsitape/stenc/issues/63