Remove multi-tap feature

Change-Id: Ife44b3f9d420d77d2cfb51044a8356f02ed63e8b
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index 549c2ae..9759e0e 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -94,8 +94,8 @@
     </declare-styleable>
 
     <declare-styleable name="Keyboard_Key">
-        <!-- The unicode value or comma-separated values that this key outputs. -->
-        <attr name="codes" format="integer|string" />
+        <!-- The unicode value that this key outputs. -->
+        <attr name="code" format="integer" />
         <!-- The characters to display in the popup keyboard. -->
         <attr name="popupCharacters" format="string" />
         <!-- Maximum column of popup keyboard -->