Use Drawer in Settings app

- get rid of PreferenceActivity as much as we can and use fragments instead
- add Drawer widget
- add Dashboard high level entry into the Drawer (but this is work in progress and would be done in another CL)
- add bypass of fragment's Header  validation when launched from the Drawer but *force* validation if external
call thru an Intent

Be aware that WifiPickerActivity should remain for now a PreferenceActivity. It is used by SetupWizard and should
not trigger running the SettingsActivity's header building code. SetupWizard is a Home during the provisionnig process
and then deactivate itself as a Home but would make the Home header to appear in the Drawer (because momentarily we
would have two Home).

Also, verified that:

- the WiFi settings still work when called from SetupWizard
- when you have multiple Launchers, the Home header will appear in the list of Headers in the Drawer

Change-Id: I407a5e0fdd843ad7615d3d511c416a44e3d97c90

src/com/android/settings/UserDictionarySettings.java

@@ -192,9 +192,8 @@ public class UserDictionarySettings extends ListFragment {
         args.putString(UserDictionaryAddWordContents.EXTRA_WORD, editingWord);
         args.putString(UserDictionaryAddWordContents.EXTRA_SHORTCUT, editingShortcut);
         args.putString(UserDictionaryAddWordContents.EXTRA_LOCALE, mLocale);
-        android.preference.PreferenceActivity pa =
-                (android.preference.PreferenceActivity)getActivity();
-        pa.startPreferencePanel(
+        SettingsActivity sa = (SettingsActivity) getActivity();
+        sa.startPreferencePanel(
                 com.android.settings.inputmethod.UserDictionaryAddWordFragment.class.getName(),
                 args, R.string.user_dict_settings_add_dialog_title, null, null, 0);
     }