OmniGears: enable button brightness settings

bring back SeekBarPreference and change to new API

Change-Id: I45387115b51370382c740e3688dae20f0641fd14
diff --git a/res/xml/button_settings.xml b/res/xml/button_settings.xml
index c363700..2053462 100644
--- a/res/xml/button_settings.xml
+++ b/res/xml/button_settings.xml
@@ -72,12 +72,12 @@
             android:persistent="false"/>
 
     </PreferenceCategory>
-<!--
+
     <PreferenceCategory
         android:key="button_keys"
         android:title="@string/button_keys_title" >
 
-        <SwitchPreference
+        <!--<SwitchPreference
             android:key="navigation_bar_show"
             android:title="@string/navigation_bar_show_title"
             android:summary="@string/navigation_bar_show_summary"
@@ -88,8 +88,8 @@
             android:title="@string/hardware_keys_disable_title"
             android:summary="@string/hardware_keys_disable_summary"
             android:persistent="false"/>
--->
-        <!--<CheckBoxPreference
+
+        <CheckBoxPreference
             android:key="virtual_key_haptic_feedback"
             android:title="@string/virtual_key_haptic_feedback_title"
             android:summary="@string/virtual_key_haptic_feedback_summary"
@@ -100,18 +100,18 @@
             android:title="@string/force_show_overflow_menu_title"
             android:summary="@string/force_show_overflow_menu_summary"
             android:persistent="false"/>-->
-<!--
+
         <PreferenceScreen
             android:key="button_brightness"
             android:title="@string/button_backlight_title"
-            android:fragment="org.omnirom.omnigears.brightness.ButtonBrightnessSettings" />
--->
+            android:fragment="org.omnirom.omnigears.ButtonBrightnessSettings" />
+
         <!--<SwitchPreference
             android:key="keys_enable_custom"
             android:title="@string/keys_enable_custom_title"
             android:persistent="false" />-->
 
-<!--    </PreferenceCategory> -->
+    </PreferenceCategory>
 <!--
     <PreferenceCategory
        android:key="button_keys_back"