Iterate over translation fields only in get_fields_to_translatable_models. Potential fix for issue #132.
Merge branch 'fix_get_fields_to_translatable_models'
Applied styleguide. We allow 100 chars now, let's use the space.
Add autodiscover tests.
Damned Python 2.5 decorators.
Fix autodiscover tests.
Remove unnecessary test methods.
Use newest versions of Django.
Flake8 fix.
Refactor translation options to be able to keep track of translation fields inherited from concrete supermodels and find fields inherited indirectly (through unregistered parents). Ensure that a base is not registered after or unregistered before submodel (that would necessitate repatching the submodel).

This changes how _registry looks, now info about all seen models is stored (including unregistered ascendants of registered models), to avoid recomputing parents options when determining translation fields of a submodel. ``TranslationOption`` instances have just two dictionaries of fields: ``local_fields`` (similar to the former ``localized_fieldnames``) and ``fields`` to match Django naming and precompute only what's necessary.
Added a README link to satisfy sdist.
Prepared 0.5 release.
Separate registry for manager shouldn't be needed any longer -- the main registry caches options for all seen models.
Now it might be possible to optimize the manager by precomputing or caching ``fields_to_translatable_models`` on translation options (instances).
Adapt management commands and a debug message (by using ``get_registered_models`` rather than directly ``registry``).
Adapt admin to new translation options, allowing it to manage translation fields inherited from concrete supermodels.
``TranslationOptions.localized_fieldnames_rev`` is no longer available, but should be replaceable by field.translated_field (may be readded as a ``TranslationOptions`` method if it's useful for something).
Test registration and translation fields inheritance with a more complex model hierarchy (inspired by Mezzanine).
Small cleanup in ``FieldsAggregationMetaClass``. The manual inheritance syntax is left mostly for backwards compatibility.
Updated changelog.
Flake8, unused variable and import.
Merge branch 'master' into feature/populate-modes-get-or-create-fixtures

Conflicts:
	modeltranslation/manager.py
	modeltranslation/translator.py