Disable panning to uncover a nil underController when pan/reveal amounts have been set for that side. Fixes ECSlidingViewController#64.

Author: Jeff Arena

ECSlidingViewController/Vendor/ECSlidingViewController/ECSlidingViewController.m

@@ -256,7 +256,8 @@ - (void)updateTopViewHorizontalCenterWithRecognizer:(UIPanGestureRecognizer *)re
     CGFloat panAmount = self.initialTouchPositionX - currentTouchPositionX;
     CGFloat newCenterPosition = self.initialHoizontalCenter - panAmount;
 
-    if ((newCenterPosition < self.resettedCenter && self.anchorLeftTopViewCenter == NSNotFound) || (newCenterPosition > self.resettedCenter && self.anchorRightTopViewCenter == NSNotFound)) {
+    if ((newCenterPosition < self.resettedCenter && (self.anchorLeftTopViewCenter == NSNotFound || self.underRightViewController == nil)) ||
+        (newCenterPosition > self.resettedCenter && (self.anchorRightTopViewCenter == NSNotFound || self.underLeftViewController == nil))) {
       newCenterPosition = self.resettedCenter;
     }