Update wordcloud.py

- Made width and height arguments
- Allow `--stopwords None` to process all
- Made the orientation configurable (from https://github.com/paul-nechifor/word_cloud/commit/d99c58dc27a0bf31671080ff7eeab7491728dbb9 )
 - Removed max_features=200 to process all
- Changed charset_error to decode_error to remove deprecation warning
- Typos