Move fakes.py into the pyrax module

It is advantageous for an application that utilizes pyrax, to have access to the fake clients used by the pyrax tests, so that you can perform unit testing on code that utilizes pyrax.

Currently, the fakes.py file is part of the tests and not shipped with pyrax on install.  python-novaclient ships it's entire tests.

As an aside, python-swiftclient does not ship it's tests or fakes with the module during installation.