- Add clear entry in menu

- clean string.xml file
-

app/src/main/res/menu/menu_main.xml

@@ -3,8 +3,9 @@
     xmlns:tools="http://schemas.android.com/tools"
     tools:context="me.zobrist.tichucounter.MainActivity">
     <item
-        android:id="@+id/action_settings"
+        android:id="@+id/action_clear"
+        android:checkable="false"
         android:orderInCategory="100"
-        android:title="@string/action_settings"
+        android:title="@string/clear"
         app:showAsAction="never" />
 </menu>