Reduce nesting, return early in error cases.

Update throttling.md

Added comma to make DEFAULT_THROTTLE_CLASSES a tuple in example, for copy&paste to work nicely.

Minor typos fixed in api-guide/testing.md (request -> response).

Add myself into credits.md

update regex for matching URLs, fixes issue #1386

Fixed Testing docs section

Closes #1210. 

Test and quick fix for #1257

Update Exceptions Documentation

* regex for matching URLs was rewritten
* added unittests

Generate random token directly

Fixed a bug backticks

fix

    you may optionally exclude the ``self.check_object_permissions, and simply return the object from the `get_object_or_404` lookup.

to

    you may optionally exclude the `self.check_object_permissions`, and simply return the object from the `get_object_or_404` lookup.

Fixes typo (Implicit instead of Implict).

Viewsets docs typo

The docstring in the example said "update" instead of "create".

fixed typo (wrong "its")

just little bit modify

Fix doc for custom exception sample

The way to provide a default detail for APIException is to define a `default_detail` attribute on the subclass.

Defining a `detail` attribute without `default_detail` will not work, and will result in empty detail instead.

Import force_bytes on django >= 1.5