nlpO3-Python 1.2.1

• Update to use nlpO3 1.3.1
• load_dict() will now return (msg, success)
  • where success is loading status (True = success, False = failed) and msg (str) can be an error message.
• segment() can now deal with None and non-str for input text
• Remove default dictionary, reduce the library size
  • so always required to supplies segment() with a dictionary name when calling it
• Exclude notebooks and tests in distribution packages
• Add unit tests