Lots of changes to support localization

cc @eickenberg. API needs a close look - if the internals need cleaning I am going to do a second PR for cleaning up examples, and probably adding a wordnet hierarchy matcher (matching dog and cat is tricky). 
This should always refer to the right directory - this code is based on the sklearn sample images (china and something else...). dirname(__file__) is to handle the differences between setup.py develop and setup.py install I believe.