Simplified some examples in tutorial

This reverts commit d6806340.

get_full_path returns unicode, so we use build_absolute_uri which
returns iri_to_uri'ed one

Simplified some functions in permissions.py

Should it be that way?

djangorestframework-camel-case in docs

sections of the docs for both parsers and renderers.

Added missing custom validation method test

Updated test class name to be unique

Fix tutorial's step 1 for Python 3

Merge branch 'nullbooleanfield_testcase' of git://github.com/dpetzel/django-rest-framework into dpetzel-nullbooleanfield_testcase

Conflicts:
	rest_framework/tests/test_serializer.py

Fix infered field type for models.NullBooleanField

Fix nested serializers with renamed fields

Merge branch 'master' of git://github.com/philipforget/django-rest-framework into philipforget-master