vlt.file.filediff

  FILEDIFF - return the output of the system tool 'diff'

  [B,D] = vlt.file.filediff(FILE1,FILE2)

  Returns the output of the system tool ['diff file1 file2]', if 'diff' exists.
  B is 0 if the files do not differ, and 1 if they do differ.
  The output of the function (the text notes of the differences) are returned in D.