New DeskClock activity, now the main app entry point.

UI not yet wired up for the most part, but Alarms should
take you to the AlarmClock activity, and there's a
functional implementation of screen dimming ("nightstand
mode").
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 9ec9d5a..cb250c5 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -13,7 +13,9 @@
 
         <provider android:name="AlarmProvider" android:authorities="com.android.deskclock" />
 
-        <activity android:name="AlarmClock" android:label="@string/app_label"
+        <activity android:name="DeskClock"
+                android:label="@string/app_label"
+                android:theme="@android:style/Theme.Wallpaper.NoTitleBar"
                 android:icon="@drawable/ic_widget_analog_clock"
                 android:configChanges="orientation|keyboardHidden|keyboard|navigation">
             <intent-filter>
@@ -24,6 +26,13 @@
             </intent-filter>
         </activity>
 
+        <activity android:name="AlarmClock" android:label="@string/alarm_list_title"
+                android:configChanges="orientation|keyboardHidden|keyboard|navigation">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+            </intent-filter>
+        </activity>
+
         <activity android:name="SettingsActivity" android:label="@string/settings">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />