Topic case-sensitivity and promise rejections during parse for v2.0.0

[kirsle]

From Botmakers Slack:

• It seems defining a > topic with capital letters raises a syntax error at parse time, and this causes the Promise from loadDirectory, etc. to reject -- which it shouldn't.
• Look into making topics case insensitive, maybe just lowercase them everywhere, even in {topic=} tags when trying to set a topic.