MAN page

[trypy]

Maybe add MAN page to github for potential edits

I see in code --check returns three possible values.

Maybe note this in MAN page and/or --help text

const char *check_status_str(int check)
{
switch (check) {
case 1:
return "OK";
case 2:
return "WARNING";
case 3:
return "ERROR";
}

return "";

}

[tjko]

Man page is included in the repository: https://github.com/tjko/jpeginfo/blob/master/jpeginfo.1

I added note about the exit code in the man page (6bcb601)