Add Home / Launcher apps indexing

- add a BaseSearchIndexProvider to HomeSettings
- use a BroadcastReceiver for tracking add or remove of
Home / Launcher apps
- add "launcher" synonym for "home" too

- also code cleaning for DynamicIndexableContentMonitor

See bug: #16484927 Add "launcher" as a synonym for "home" in settings search

Change-Id: I819f4e5f7bd5e9a7882609206b2733ea1912fc69

src/com/android/settings/SettingsActivity.java

@@ -294,7 +294,6 @@ public class SettingsActivity extends Activity
 
     private boolean mBatteryPresent = true;
     private BroadcastReceiver mBatteryInfoReceiver = new BroadcastReceiver() {
-
         @Override
         public void onReceive(Context context, Intent intent) {
             String action = intent.getAction();