Fix changing the colour based on value of prediction

Everything was coming through as full blue because of an error in the equation.
Created an express app to handle both the static content and providing forecast data

Everything is now bundled into a sing app
Can use environment variable for the API key
Updated the angular service to point at the node app
Deleted the wrong line in the last commit :-)
Don't need to ignore the config.js file anymore

The API key is stored as an environment variable
Add Procfile