Removed a mutable default param in Serializer.serialize().

I haven't seen this pop up explicitly as a bug in code; only noticed it
through code inspection.
Raise ApiFieldError on invalid datetimes
Update docs/who_uses.rst

Added dbpatterns to who uses
If no object_class is present, do not try to instantiate an object when building the bundle. This does not affect model-based resources; however, the assumption that had been made that an object_class is always going to be present is not valid when using custom Resource objects that are not necessarily model-based.
Fixes cookbook entry for "Creating per-user resources".

Incorrect after https://github.com/toastdriven/django-tastypie/commit/d850758b088761a00f60a474f5b2d683dc1ec3c0#L4L1258
Fixes build by dropping python 2.5, and adds django 1.5 support to tox.
Update configuration warning to mention defusedxml

This is mentioned in the README & docs but should also be mentioned in
the actual ImproperlyConfigured exception which is raised when you try
to use XML without all of the dependencies.
Added optional setting, 'TASTYPIE_ABSTRACT_APIKEY', which, if set to 'True', will make 'models.ApiKey' an abstract base class.
Adding OAuth 2.0 tutorial information in cookbook
Included note re: syncdb when using ApiKey model. Closes #909.
Updates setup.py - corrects name of requirement

python-dateutil instead of python_dateutil
Fixes #884. Authorization for update should be only called once with a fully hydrated bundle
Fixes #850. Instead of using path to determin if we are dehydrating a list of resources or a single resource, we explicitly pass a boolean. This should also make writing tests easier as we no longer need to have path defined for requests.
Merge pull request #913 from ClearcodeHQ/master

Fixes requirement name
Only save related models if they've changed; closes #397, #594 and others.

Extra tests assuring through model metadata is saved; fixing backwards/forwards incompatability with MockRequest
Ignore the env3 virtualenv.
Backfilled release notes.
Added release notes for v0.9.15.
Bumped version to v0.9.15!
Started v0.9.16-dev.