SDK only: now that support lib is in SDK, we can link to it.

Update some of the platform documentation to directly link to
relevent support lib docs.  Yay!

Also improve BroadcastReceiver documentation to more clearly
discussion security around receivers, and how the support
lib's LocalBroadcastManager can help.

Change-Id: I563c7516d5fbf91ab884c86bc411aff726249e42
diff --git a/core/java/android/content/Loader.java b/core/java/android/content/Loader.java
index 2d2a90d..ac05682 100644
--- a/core/java/android/content/Loader.java
+++ b/core/java/android/content/Loader.java
@@ -58,6 +58,13 @@
     boolean mReset = true;
     boolean mContentChanged = false;
 
+    /**
+     * An implementation of a ContentObserver that takes care of connecting
+     * it to the Loader to have the loader re-load its data when the observer
+     * is told it has changed.  You do not normally need to use this yourself;
+     * it is used for you by {@link CursorLoader} to take care of executing
+     * an update when the cursor's backing data changes.
+     */
     public final class ForceLoadContentObserver extends ContentObserver {
         public ForceLoadContentObserver() {
             super(new Handler());
@@ -74,6 +81,14 @@
         }
     }
 
+    /**
+     * Interface that is implemented to discover when a Loader has finished
+     * loading its data.  You do not normally need to implement this yourself;
+     * it is used in the implementation of {@link android.app.LoaderManager}
+     * to find out when a Loader it is managing has completed so that this can
+     * be reported to its client.  This interface should only be used if a
+     * Loader is not being used in conjunction with LoaderManager.
+     */
     public interface OnLoadCompleteListener<D> {
         /**
          * Called on the thread that created the Loader when the load is complete.