Add __init__ to repo root for subclassing
Add __init__ to repo root for subclassing

Add an __init__.py to the git repo root to make it easier to subclass
rivescript.

aichaos/rivescript-python,plasmashadow/rivescript-python,aichaos/rivescript-python,plasmashadow/rivescript-python,FujiMakoto/makoto-rivescript,FujiMakoto/makoto-rivescript,FujiMakoto/makoto-rivescript,plasmashadow/rivescript-python,Dinh-Hung-Tu/rivescript-python,aichaos/rivescript-python,Dinh-Hung-Tu/rivescript-python,Dinh-Hung-Tu/rivescript-python