no --version on OS X #35

Traceback (most recent call last):
  File "/usr/local/bin/python-keepass-httpd", line 11, in <module> 
    sys.exit(main())
  File "/Library/Python/2.7/site-packages/keepass_http/scripts/python_keepass_httpd.py", line 69, in main
    backend = backends.BaseBackend.get_by_filepath(database_path)
  File "/Library/Python/2.7/site-packages/keepass_http/backends/__init__.py", line 73, in get_by_filepath
    mimetype = mimetypes.guess_type(filepath)[0]
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/mimetypes.py", line 295, in guess_type
    return _db.guess_type(url, strict)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/mimetypes.py", line 114, in guess_type
    scheme, url = urllib.splittype(url)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib.py", line 1071, in splittype
    match = _typeprog.match(url)
TypeError: expected string or buffer