title: Create a Dataframe of All Dates in the year 2015
body: <p>I am interested in creating a dataframe of <code>Date</code> values for the year 2015. There would be one row per date. Also, these would have to correspond to their accurate weekday. For example <code>weekdays()</code> applied to <code>2015-01-01</code> would have a value of <code>Thursday</code>. This is because I ultimately want to extract the dates that correspond to Saturdays and Sundays.</p>