Very slow due to repeated unnecessary sorting

[trevoriancox]

In TouchCalendarEventsBase.js, sort is called on eventStore repeatedly, for every date. In my test, moving sort() to before dates.each() reduced the time to display a new month in month view from 3 secs to 0.5 secs (with 300 event records, Chrome desktop browser).

dates.each(function(dateObj){
            var currentDate = dateObj.get('date'),
                currentDateTime = currentDate.getTime(),
                takenDatePositions = []; // stores 'row positions' that are taken on current date

            // sort the Events Store so we have a consistent ordering to ensure no overlaps
            eventStore.sort(this.getPlugin().getStartEventField(), this.getEventSortDirection());

[trevoriancox]

Also I think we should make the eventStore sort optional (skip if StartEventField is not set), as the eventStore may already be appropriately sorted.