Generate KeyboardLabelsSet from donottranslate-more-keys.xml

This change introduces makelabel tool that reads all languages'
donottranslate-more-keys and generate KeyboardLabelsSet.java source
file. The makelabel command must be invoked prior to compile LatinIME.

Change-Id: I7515c7919c535e30f9c80a37bdc831d0f682cd43
diff --git a/java/res/xml/keys_parentheses.xml b/java/res/xml/keys_parentheses.xml
index 502a84e..17d7285 100644
--- a/java/res/xml/keys_parentheses.xml
+++ b/java/res/xml/keys_parentheses.xml
@@ -24,9 +24,9 @@
     <Key
         latin:keyLabel="("
         latin:code="!code/key_left_parenthesis"
-        latin:moreKeys="@string/more_keys_for_left_parenthesis" />
+        latin:moreKeys="!label/more_keys_for_left_parenthesis" />
     <Key
         latin:keyLabel=")"
         latin:code="!code/key_right_parenthesis"
-        latin:moreKeys="@string/more_keys_for_right_parenthesis" />
+        latin:moreKeys="!label/more_keys_for_right_parenthesis" />
 </merge>