Move argument checking to argparse

Here is a small patch to add some of the arg checking functionality into arg parse.  This also updates the output of -h and --help so one know shwat arguments to use.  The patch looks much bigger then it actually is due to a change in the white space indention  The only changes acutely made are here https://github.com/b4ldr/osueta/blob/master/osumain.py#L47-L70.