more general test calendar cleanup

tests/lib/jasmine-ext.js

@@ -223,8 +223,8 @@ beforeEach(function() {
 
 });
 
-// Destroy the calendar afterwards, to prevent memory leaks
+// Destroy all calendars afterwards, to prevent memory leaks
 // (not the best place for this)
 afterEach(function() {
-	$('#calendar,#cal').fullCalendar('destroy'); // common id's for calendars in tests
+	$('.fc').fullCalendar('destroy');
 });