Deprecate -initWith{View,Layer}Class:.

These have been superseded by -[ASDisplayNode initWithViewBlock:] and
-[ASDisplayNode initWithLayerBlock:], respectively -- the new API allows
for custom initialisers, but does not support asynchronous display.

The old initialisers are still available in ASDisplayNodeInternal.h, for
internal subclasses and daring adventurers.

AsyncDisplayKitTests/ASDisplayLayerTests.m

@@ -48,6 +48,12 @@ static UIImage *bogusImage() {
 @end
 
 
+@interface ASDisplayNode (HackForTests)
+- (id)initWithViewClass:(Class)viewClass;
+- (id)initWithLayerClass:(Class)layerClass;
+@end
+
+
 @interface _ASDisplayLayerTestLayer : _ASDisplayLayer
 {
   BOOL _isInCancelAsyncDisplay;