Add an example for the connection class

Also, change around the other examples to use the connection
example so there isn't duplication of code for session and
authentication.

Change-Id: I90dbcfac3eae0c792bd9c4eae071de7d81e1b27d
Add resource CRUD to connection class

Once a user has a resource, there is no need to use the proxy
to perform operations on it.  These CRUD methods allow the user
to perform them direction on the object.  For instance:

    project = conn.identity.find_project('foo')
    project['enabled'] = False
    conn.update(project)

Change-Id: I801de6b56f2f44c568b6edcf9c1429014f42a65f
Have resource CRUD return self to simplify the proxies

Instead of:
    def create_project(self, **data):
        obj = project.Project(**data)
        obj.create(self.session)
        return obj

We can:
    def create_project(self, **data):
        return project.Project(**data).create(self.session)

Change-Id: Ifbb41c7d1de461c80ea98b2c3d2e715da770a07f
Updated from global requirements

Change-Id: I3f81b59a1d5e0fc1aaf48e987404a5744d1bd2ad
Merge "Add resource CRUD to connection class"
Merge "Add an example for the connection class"