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/rowkeys_symbols2.xml b/java/res/xml/rowkeys_symbols2.xml
index 1092421..47865a9 100644
--- a/java/res/xml/rowkeys_symbols2.xml
+++ b/java/res/xml/rowkeys_symbols2.xml
@@ -28,21 +28,21 @@
     <Key
         latin:keyStyle="currencyKeyStyle" />
     <Key
-        latin:keyLabel="@string/keylabel_for_symbols_percent"
-        latin:moreKeys="@string/more_keys_for_symbols_percent" />
+        latin:keyLabel="!label/keylabel_for_symbols_percent"
+        latin:moreKeys="!label/more_keys_for_symbols_percent" />
     <Key
         latin:keyLabel="&amp;" />
     <Key
         latin:keyLabel="*"
-        latin:moreKeys="@string/more_keys_for_star" />
+        latin:moreKeys="!label/more_keys_for_star" />
     <!-- U+2013: "–" EN DASH
-             U+2014: "—" EM DASH -->
+         U+2014: "—" EM DASH -->
     <Key
         latin:keyLabel="-"
         latin:moreKeys="_,&#x2013;,&#x2014;" />
     <Key
         latin:keyLabel="+"
-        latin:moreKeys="@string/more_keys_for_plus" />
+        latin:moreKeys="!label/more_keys_for_plus" />
     <include
         latin:keyboardLayout="@xml/keys_parentheses" />
 </merge>