Added missed header

Author: aint

app/res/drawable/numeric_button.xml

@@ -1,4 +1,21 @@
 <?xml version="1.0" encoding="utf-8"?>
+
+<!--
+ Copyright (c) 2014 Oleksandr Tyshkovets <olexandr.tyshkovets@gmail.com>
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
     <item android:state_pressed="true" >
         <shape>