Fix issues with contextual menu in calendars

Creating an event or a task using the contextual menu will now consider
the day and hour of the menu position (fixes #2557).
The next/previous day/month menu options have been fixed.
The menu will now disappear when clicking outside the contextual menu on
the calendar area.

UI/Templates/SchedulerUI/UIxCalMonthView.wox

@@ -23,6 +23,7 @@
     <span class="monthsHeader">
       <span class="month1">
         <a href="#"
+           id="leftNavigationArrow"
            var:date="prevMonthQueryParameters.month"
            onclick="return onCalendarGotoDay(this);"
            ><img rsrc:src="arrow-left.png"/></a>
@@ -30,6 +31,7 @@
       <span class="month0"><var:string value="monthNameOfThisMonth" /></span>
       <span class="month1">
         <a href="#"
+           id="rightNavigationArrow"
            var:date="nextMonthQueryParameters.month"
            onclick="return onCalendarGotoDay(this);"><img rsrc:src="arrow-right.png"/></a>
       </span>