Add `layer` to the view explorer shortcut property list.

Classes/Object Explorers/FLEXViewExplorerViewController.m

@@ -56,7 +56,7 @@ typedef NS_ENUM(NSUInteger, FLEXViewExplorerRow) {
 
 - (NSArray *)shortcutPropertyNames
 {
-    NSArray *propertyNames = @[@"frame", @"bounds", @"center", @"transform", @"backgroundColor", @"alpha", @"opaque", @"hidden", @"clipsToBounds", @"userInteractionEnabled"];
+    NSArray *propertyNames = @[@"frame", @"bounds", @"center", @"transform", @"backgroundColor", @"alpha", @"opaque", @"hidden", @"clipsToBounds", @"userInteractionEnabled", @"layer"];
     
     if ([self.viewToExplore isKindOfClass:[UILabel class]]) {
         propertyNames = [@[@"text", @"font", @"textColor"] arrayByAddingObjectsFromArray:propertyNames];