import channel.pp and rspec tests

this allows subscribing to redhat channels via the defined type
spacewalk::channel. it also supports custom channels with custom pgp
keys used for signing.

you also need to specify a username/password for accessing the satellite
server. subscribing to channels works with an unprivileged user, so you
should create one.

i've also included rspec tests for the defined type spacewalk::channel.
import .fixtures.yml and a Rakefile for rspec
tests/init.pp was missing for running puppet apply

this allows module testing with puppet apply tests/init.pp.
Merge pull request #1 from tosmi/channel

add support to subscribe/unsubscribe to rhn channels
make spacewalk_client_repo optional, support reregistration

introduced two new options to spacewalk::client

- force_registration: if set to yes, the client is going to reregister
  itself to the spacewalk server on the next run. use with care as this
  can result in the same system registered more than once on the server.

- use_spacewalk_client_repo: if spacewalk::client should configure the
  spacewalk client repository and exec setupSpacewalkClientRepo.

  when using a redhat satellite server, the client repo is not needed.
import rspec tests for client.pp
added stdlib to dependencies
Merge branch 'client' of github-socks:tosmi/puppet-spacewalk into client

Conflicts:
	.fixtures.yml
	manifests/client.pp
	spec/classes/client_spec.rb