Implemented Exercises Timetable

Hoping this looks alright to you. I've got quite a bit of work to do on the timeline to get it nice and smooth, I'm not quite sure how Heroku works but might be best to link it to the github rather than local links to the file? Despite this, probably best to package it together.

## README Alterations
Also I've updated the readme with a refreshed todo list and a guide to how to get started developing. I know you'd already dropped the paragraph on how to get development up and running real quick but I reckon some first years who want to contribute to something like this would most likely be dissuaded by the obfuscation caused by the mix of ruby, rails, coffeescript, haml. They've most likely never came across anything like it, so it's nice to have a good explanation to get started with. 

## Future Plans
Basic plans for the future include choice selection of the modules displayed in the exercises page with the plan to have the generation of the timeline bound to a click event of a selection. That way I can avoid crushing the js engine with about 1000 items to animate at once. Works fine once everything's loaded though, and the parser for the exercises seems pretty solid. Also intend to create a condensed version- maybe just two weeks centred around the current date for inclusion on the dashboard page. At that timescale it probably wouldn't be too much of a squeeze to shove all the modules onto the one timeline, along with that being a convenient time to scrape the modules behind the scene.

## Summary TODO
1. Create selection of modules to display on the exercises page
2. Implement a condensed timeline for the dashboard
3. Implement shadow colour coding of each exercise label to represent done, in progress or future. Probably green, red and blue respectively.
4. Generally clean up the timeline script, ~650 loc is absurd.