CakePHP 1.3: Fix search_hanzi_kanji route

For some reason, the default action route for search_hanzi_kanji isn’t
working anymore. That is, going to /tools/search_hanzi_kanji isn’t
catched by that route anymore. One must always give the complete URL
that includes the action, like /tools/search_hanzi_kanji/index. Since
we want backward compatibility for search engines, I added the
action-less version of the route.