Added a screen to configure wireless scanning

- Created "Scanning" preference screen

- Added overflow menu on "Location" settings to access "Scanning" settings

- Moved "Wi-Fi scanning always available" from Wi-Fi settings to "Scanning"
  settings

- Added "Bluetooth scanning always available" preference (UI only)

Change-Id: I85d8cd60ab309db5db9caee43f4b5a117192d904

res/xml/location_scanning.xml

@@ -0,0 +1,34 @@
+<?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.
+-->
+
+<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
+        android:title="@string/location_scanning_screen_title">
+
+        <SwitchPreference
+            android:title="@string/location_scanning_wifi_always_scanning_title"
+            android:summary="@string/location_scanning_wifi_always_scanning_description"
+            android:defaultValue="true"
+            android:key="wifi_always_scanning"
+            android:persistent="false" />
+
+        <SwitchPreference
+            android:title="@string/location_scanning_bluetooth_always_scanning_title"
+            android:summary="@string/location_scanning_bluetooth_always_scanning_description"
+            android:defaultValue="true"
+            android:key="bluetooth_always_scanning"
+            android:persistent="false" />
+
+</PreferenceScreen>

res/xml/wifi_advanced_settings.xml

@@ -24,12 +24,6 @@
             android:summary="@string/wifi_notify_open_networks_summary"
             android:persistent="false" />
 
-    <SwitchPreference
-            android:key="wifi_scan_always_available"
-            android:title="@string/wifi_scan_always_available"
-            android:summary="@string/wifi_scan_always_available_summary"
-            android:persistent="false" />
-
     <ListPreference
             android:key="sleep_policy"
             android:title="@string/wifi_setting_sleep_policy_title"