Add support for prefetched translations
Fix prefetched translations for Django 1.4 and Django 1.5
Merge pull request #9 from bikeshedder/master

Add support for prefetched translations
Update CHANGELOG
Added tests for query counts.
Added _get_translated_queryset(), removes duplicate code
Optimization, also cache prefetched data locally.
Optimize _get_translated_model() when prefetched data has no result.

If the object is not found in the prefetched data, there is no point in
checking memcached or perform a single query afterwards. Directly jump
to trying the fallback language.
Fix unittests for python 3