Add read-only names to UIView and CALayer

- Backed by name of the underlying ASDisplayNode.
- Remove goofy usages of `setValue:forKey:` in ASDisplayNodeTests and ASDisplayNodeAppearanceTests.

AsyncDisplayKit/ASDisplayNode.h

@@ -650,6 +650,7 @@ typedef void (^ASDisplayNodeDidLoadBlock)(ASDisplayNode *node);
  * @param node The node to be added.
  */
 - (void)addSubnode:(ASDisplayNode *)node;
+- (NSString *)name;
 @end
 
 /** CALayer(AsyncDisplayKit) defines convenience method for adding sub-ASDisplayNode to a CALayer. */
@@ -660,6 +661,7 @@ typedef void (^ASDisplayNodeDidLoadBlock)(ASDisplayNode *node);
  * @param node The node to be added.
  */
 - (void)addSubnode:(ASDisplayNode *)node;
+- (NSString *)name;
 @end
 
 @interface ASDisplayNode (Deprecated)

AsyncDisplayKit/ASDisplayNode.mm

@@ -2203,6 +2203,11 @@ static const char *ASDisplayNodeAssociatedNodeKey = "ASAssociatedNode";
   }
 }
 
+- (NSString *)name
+{
+  return self.asyncdisplaykit_node.name;
+}
+
 @end
 
 @implementation CALayer (AsyncDisplayKit)
@@ -2212,6 +2217,11 @@ static const char *ASDisplayNodeAssociatedNodeKey = "ASAssociatedNode";
   [self addSublayer:node.layer];
 }
 
+- (NSString *)name
+{
+  return self.asyncdisplaykit_node.name;
+}
+
 @end