Fix relative dates

Simplified the RelativeDate logic to the following:

    if date is in future or more than 365 days in past, just display the date in yyyy-mm-dd format.

    else if date is more than 30 days in the past, display 'N months ago', where 1 month is considered 30 days. 
    This isn't very accurate, but it should be good enough for our purpose here.

    else if date is more than 1 day in the past, display 'N days ago'

    else display 'today'.

Fixes #289