[appledoc] Include subclassing header.

Use `--no-merge-categories` to prevent subclassing-only documentation
from appearing in the general API reference.  Use consistent category
names.

AsyncDisplayKit/ASControlNode+Subclasses.h

@@ -8,7 +8,7 @@
 
 #import <AsyncDisplayKit/ASControlNode.h>
 
-@interface ASControlNode (ForSubclassesEyesOnly)
+@interface ASControlNode (Subclassing)
 
 /**
  @abstract Sends action messages for the given control events.

AsyncDisplayKit/ASDisplayNode+Subclasses.h

@@ -34,7 +34,7 @@
  * variables.
  */
 
-@interface ASDisplayNode (ASDisplayNodeSubclasses)
+@interface ASDisplayNode (Subclassing)
 
 
 /** @name View Configuration */

docs/build.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 set -e
 
-HEADERS=`ls ../AsyncDisplayKit/*.h | grep -v Subclasses`
+HEADERS=`ls ../AsyncDisplayKit/*.h`
 
 rm -rf htdocs appledoc
 
@@ -12,6 +12,7 @@ appledoc \
     --create-html \
     --exit-threshold 2 \
     --no-repeat-first-par \
+    --no-merge-categories \
     --project-name AsyncDisplayKit \
     --project-company Facebook \
     --company-id "com.facebook" \