Filter to see features only for a specific version of Web Essentials

With the arrival of Web Essentials 2015, a filter will be useful to allow the user to see only features for the version required.

Because all node.js compilers have been removed. I tried to [exclude all articles related for that](d3626132b6f40b97784f9409ad9adfe3dc924a8b) but you feel free to remove others if I missed them. 

Result on screen:
![image](https://cloud.githubusercontent.com/assets/1680372/5195468/393d1ce0-74eb-11e4-9f7b-d98284891b28.png)

Result on mobile:
![image](https://cloud.githubusercontent.com/assets/1680372/5195476/6340580e-74eb-11e4-8b42-cc7e20ac5ad8.png)