Sorted Celery, I had implemented it WRONG!

Added Celery and Helper to requirements.txt.
Using Flask-Celery-Helper as it saves duplicating work.
Added RabbitMQ to Travis-CI (not using yet though)
Remove PyPy from Travis config.
Removed un-used LUA script (not really needed since MongoDB)
Removed tasks.py in lib/ because it wasn't doing it for me.