Convert the msg timestamp into a datetime object to make the date available in the card
Small HTML fixes, add the date to the card and fix link to the individual message by its id
Make sure the dates are converted in UTC
Use arrow to parse the date from the raw_message
Display the date in full if size == 'large' otherwise just the relative date provided by arrow

To do this we need to forward the size argument to the template
Merge pull request #105 from fedora-infra/add_dates

Add dates