Updates for Rspec 2.*

These commits simply update all the code that is still referring to pre-2.0 spec constants.  The end effect is just the removal of deprecation warnings when running tests that require capistrano-spec.  Included is also a Bundler Gemfile for getting the environment setup properly for running the sole test for the gem itself.

I realize this changes the Rakefile, but that has the same problems with outdated task names.

Thanks for the great gem, it's awesome to have a framework for testing Cap tasks.