Make LocalePicker Fragment.

The logic calling selectFirst() is removed as
- There's no comment why it is needed.
- Actually SetupWizard gets stack as that forces users to see
  WirelessSettings in SetupWizard.

The other changes:
- Move back LocalePickerFragment to LocalePicker.
- Make <activity> for LocalePicker in AndroidManifest <activity-alias>
- Add a short comment about how getComponent(), which should be a key
  for understanding how top-level settings work.
- Modify LanguageSettings so that it corectly points LocalePicker as
  a fragment.

Change-Id: I78d356e40af896ba1aab72fba12c90467371c7b0

src/com/android/settings/Settings.java

@@ -87,6 +87,11 @@ public class Settings extends Activity
             if (initialFragment != null) {
                 showFragment(initialFragment, initialArguments);
             } else {
+                // Intent#getCompontent() lets us get Fragment name, even when the Intent is
+                // given via <activity-alias>.
+                //
+                // e.g. When we reach here via "ChildSetting" activity-alias,
+                // we should get the name here instead of targetActivity ("Settings").
                 if (intent.getComponent().getClassName().equals(this.getClass().getName())) {
                     showFragment(TopLevelSettings.class.getName(), null);
                 } else {