Factory Boy 2.0 have removed the "extracted_key" keyword argument from
post_generation() hook. Until we can update tests to work with 2.0 make
dependency on 1.3.x branch. In turn, the update got stalled by a bug
in Factory Boy (https://github.com/rbarrois/factory_boy/issues/53).

It's still not working completely (you can't run tests from it) but it's enough for installing. Fixes #18

TastyPie 0.9.13 doesn't install (reported upstream at
https://github.com/toastdriven/django-tastypie/issues/873) so use
0.9.12 for now.

This commit is a foundation upon a more robust image fetching code
will be built in the future, and it already fixes at least one weird
issue I've seen.

Use forked django-images for now, until we can communicate with the
upstream about it. Fixes #4