Add weather icons to forecast. Use updated ical parser to convert UTC. Feed URL in config.

A set of small changes to make it easier to use. 

Added weather icons to the upcoming forecast.

Moved the feed url into `js/config.js`. Also added a tiny bit of documentation on what to use for imperial units.

Updated the ical parser to use the [j08lue](https://github.com/j08lue/JavaScript-Ical-Parser) fork, which takes the ical feed as UTC and converts to local time. 

May improve it to support multiple news feeds and multiple calendars… eventually