Add support for command line arguments

Used argparse to enable command line arguments for
  user supplied options. Defaults values have been
  kept, so behavior with no arguments is the same.
  Should be easier than modifying the source each
  time this way.

Also added a gitignore file that is the standard
  github python gitignore, plus *~ to handle
  deleted files.
Merge pull request #1 from altf4/args

Add support for command line arguments