Fix missing activity declaration

Author: southrop

AndroidStudioProjects/ARMarkerDistanceProj/aRMarkerDistance/src/main/AndroidManifest.xml

@@ -31,6 +31,7 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity android:name="org.artoolkit.ar.base.camera.CameraPreferencesActivity" />
     </application>
 
 </manifest>