Code tidying, solidifying and bug fixing

* Clean up Rakefile spec tasks (separate integration_test)
* Clean up VCloud/Vcloud module mixture
* Handle a bad template name being specified
* rename vcloud-provision to vcloud-launch in docs
* move FogInterface under Vcloud module
Merge pull request #7 from alphagov/further_code_tidy

Code tidying, solidifying and bug fixing