Syntax: DATA file

   Use file "file" as the source of data read with the READ command.
The file is assumed to have numerical data in columns separated by
spaces, tabs or commas. The range of lines specified by LINES is
reset. If the file can't be opened for read, you will be warned.
Lines starting with # or ! are comments, # lines are echoed to the
terminal if VERBOSE is 2 or more, ! lines are always echoed.
