Moved cms.py's argument parsing into parse_args.py

usage: cms.py [-h] [-n] [-e N]

LazyPyCMS - a simple Python-based web CMS

optional arguments:
  -h, --help      show this help message and exit
  -n, --new       Create a new post
  -e N, --edit N  Edit an existing post in the LazyPyCMS editor.
                  Give the post number