Fixed authentication UI - it will now save the token to persistent storage and the logout button deletes the stored token

app/src/main/res/layout/activity_authenticate.xml

@@ -4,16 +4,10 @@
     android:layout_height="fill_parent"
     android:orientation="vertical">
 
-    <TextView
-        android:id="@+id/versionTv"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="Android OpenSeizureDetector Version x.xx" />
-
     <ImageView
         android:layout_width="match_parent"
         android:layout_height="64dp"
-        android:background="#FFFFBB33"
+        android:background="#FFFFFF"
         android:contentDescription="@string/app_name"
         android:scaleType="center"
         android:src="@drawable/star_of_life_24x24" />