[Android] Fixes #2247, enable hardware acceleration by default.

Setting android:hardwareAccelerated="true" seems to fix some random behaviors
in certain devices like the XperiaE.

Ref: http://developer.android.com/guide/topics/graphics/hardware-accel.html

android-project/AndroidManifest.xml

@@ -20,7 +20,8 @@
     <application android:label="@string/app_name"
                  android:icon="@drawable/ic_launcher"
                  android:allowBackup="true"
-                 android:theme="@android:style/Theme.NoTitleBar.Fullscreen">
+                 android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
+                 android:hardwareAccelerated="true" >
         <activity android:name="SDLActivity"
                   android:label="@string/app_name"
                   android:configChanges="keyboardHidden|orientation"