update to show last comment time (for #200)

Apologies that this is so messy...

The news controller contains a new function which adds the date and id of the user of the latest comment, which is then added as data attributes to the comment link item in the index template. 

I had been messing around with options for storage to keep track of and alert users when a new comment is posted but decided just adding the time of the latest comment to the index template and this more or less works for me. The end result adds no new dependencies and doesn't end up affecting main.js