BREAKING CHANGE

When trailing_slash is set to True, the router no longer will adjust the lookup regex to allow it to include periods. To simulate the old behavior, the programmer should specify `lookup_regex = '[^/]+'` on the viewset.

https://github.com/tomchristie/django-rest-framework/pull/1328#issuecomment-31517099

This patch allows a viewset to define a pattern for its lookup field, which the router will honor. Without this patch, any characters are allowed in the lookup field, and overriding this behavior requires subclassing router and copying and pasting the implementation of get_lookup_regex.

It's possible it would be better to remove this functionality from the routers and simply expose a parameter to get_lookup_regex which allows overriding the lookup_regex. That way the viewset config logic could be in the a subclass, which could invoke the super method directly.

I'm using this now for PostgreSQL UUID fields using https://github.com/dcramer/django-uuidfield . Without this patch, that field passes the lookup string to the database driver, which raises a DataError to complain about the invalid UUID. It's possible the field ought to signal this error in a different way, which could obviate the need to specify a pattern.

Conflicts:
	.travis.yml
	docs/api-guide/routers.md
	rest_framework/compat.py
	tox.ini

Simplified some examples in tutorial

This reverts commit d6806340.

When many tab's are open (which is necessary for DRF's documentation), it becomes impossible to determine which tab contains which pieces of documentation.  That they are all related is obvious by the use of a common icon, just not the specific page each tab is loaded to.

This change inverts the order of the title to maintain as much useful context as possible on the tabbar.

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