Update summary only files

The process option UPDSUMO produces an update file of 4 lines: new file name, old file name, column headers, and a summary totals line.

The UPDSUMO process option is available for the LINE, WORD, and BYTE compare types.

The summary totals line has a T in column 1. The summary statistics are located at fixed offsets in the output line. The file has a line length of 132 bytes.