Bump to awesome_nested_set 3.0.0.rc.3
Fix states_required references for countries that don't actually need states

See:

* http://en.wikipedia.org/wiki/Address_(geography)#Switzerland
* http://bitboost.com/ref/international-address-formats/switzerland/
* http://geneva.angloinfo.com/information/housing/post-codes/
* http://en.wikipedia.org/wiki/Address_(geography)#Malaysia

And other online sources.  May need to review additional countries referenced in d0585271b7bc8a285b7ffdbeb1af45bdfece1e22