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/inputmethod/KeyboardLayoutDialogFragment.java

@@ -17,7 +17,6 @@
 package com.android.settings.inputmethod;
 
 import com.android.settings.R;
-import com.android.settings.Settings.KeyboardLayoutPickerActivity;
 
 import android.app.AlertDialog;
 import android.app.Activity;
@@ -29,7 +28,6 @@ import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.Loader;
-import android.content.res.Resources;
 import android.hardware.input.InputDeviceIdentifier;
 import android.hardware.input.InputManager;
 import android.hardware.input.KeyboardLayout;