Add special present method that doesn't require an anchor point

Author: scastria

WYPopoverController/WYPopoverController.h

@@ -104,6 +104,8 @@ typedef NS_OPTIONS(NSUInteger, WYPopoverArrowDirection) {
                permittedArrowDirections:(WYPopoverArrowDirection)arrowDirections
                                animated:(BOOL)animated;
 
+- (void)presentPopoverAsDialogAnimated:(BOOL)animated;
+
 - (void)dismissPopoverAnimated:(BOOL)animated;
 
 @end

WYPopoverController/WYPopoverController.m

@@ -1610,6 +1610,11 @@ - (void)presentPopoverFromBarButtonItem:(UIBarButtonItem *)item permittedArrowDi
     [self presentPopoverFromRect:itemView.bounds inView:itemView permittedArrowDirections:arrowDirections animated:aAnimated];
 }
 
+- (void)presentPopoverAsDialogAnimated:(BOOL)aAnimated
+{
+    [self presentPopoverFromRect:CGRectZero inView:nil permittedArrowDirections:WYPopoverArrowDirectionNone animated:aAnimated];
+}
+
 - (void)positionPopover
 {
     CGSize contentViewSize = self.contentSizeForViewInPopover;