Support addtionalMoreKeys

This change also removes
  * Unused more_keys_for_q, w, and p.

Change-Id: Idb99e5f6d8c2ad2d28437f42b35b21c282cd181f
diff --git a/java/res/xml-sw600dp/rows_symbols.xml b/java/res/xml-sw600dp/rows_symbols.xml
index e345a23..701c354 100644
--- a/java/res/xml-sw600dp/rows_symbols.xml
+++ b/java/res/xml-sw600dp/rows_symbols.xml
@@ -30,33 +30,43 @@
     >
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_1"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_1"
             latin:moreKeys="@string/more_keys_for_symbols_1" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_2"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_2"
             latin:moreKeys="@string/more_keys_for_symbols_2" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_3"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_3"
             latin:moreKeys="@string/more_keys_for_symbols_3" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_4"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_4"
             latin:moreKeys="@string/more_keys_for_symbols_4" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_5"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_5"
             latin:moreKeys="@string/more_keys_for_symbols_5" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_6"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_6"
             latin:moreKeys="@string/more_keys_for_symbols_6" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_7"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_7"
             latin:moreKeys="@string/more_keys_for_symbols_7" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_8"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_8"
             latin:moreKeys="@string/more_keys_for_symbols_8" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_9"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_9"
             latin:moreKeys="@string/more_keys_for_symbols_9" />
         <Key
             latin:keyLabel="@string/keylabel_for_symbols_0"
+            latin:additionalMoreKeys="@string/additional_more_keys_for_symbols_0"
             latin:moreKeys="@string/more_keys_for_symbols_0" />
         <Key
             latin:keyStyle="deleteKeyStyle"