vpn2: show third-party VPN services

VPN apps are shown alongside configured VPNs now. The requirement that
a password is set is now only enforced when setting up a configured
VPN as this is not necessary for apps.

Some UI redesign.

Bug: 19573824
Bug: 17474682
Bug: 19575658
Change-Id: I02bd977136929647d65b9784fb4cc5df24b45428

res/layout/preference_vpn.xml

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2015 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<LinearLayout
+        xmlns:android="http://schemas.android.com/apk/res/android"
+        android:layout_width="wrap_content"
+        android:layout_height="match_parent"
+        android:orientation="horizontal">
+    <View
+        android:id="@+id/divider_manage"
+        android:layout_width="2dip"
+        android:layout_height="match_parent"
+        android:layout_marginTop="5dip"
+        android:layout_marginBottom="5dip"
+        android:background="@android:drawable/divider_horizontal_dark" />
+    <ImageView
+        android:id="@+id/manage"
+        android:layout_width="wrap_content"
+        android:layout_height="fill_parent"
+        android:paddingStart="16dip"
+        android:paddingEnd="16dip"
+        android:src="@drawable/ic_sysbar_quicksettings"
+        android:contentDescription="@string/settings_label"
+        android:layout_gravity="center"
+        android:background="?android:attr/selectableItemBackground" />
+</LinearLayout>

res/layout/vpn_dialog.xml

@@ -20,7 +20,7 @@
     <LinearLayout android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:orientation="vertical"
-            android:padding="3mm">
+            android:padding="8dp">
 
         <LinearLayout android:id="@+id/editor"
                 android:layout_width="match_parent"