New cucumber test to detect live issue #7
Fail fast if not ready
Perform validation at action execution time. 

By default Vagrant performs config validation for ALL plugins at EVERY command execution. This would cause simple commands like `vagrant ssh` or `vagrant status` to fail if the `adam.provision_url` is not configured in a `Vagrantfile` for example.
Only run provision script job if in config

Should fix #7, as now it won't run if config value is empty.
Spacing
Fixed specs for when adam config absent

Basic unit test to say it shouldn't run the provision script if the config value hasn't been set.
Improve error messages for invalid config
Change cucumber error detection spec...

To new value
New cucumber feature to check invalid urls
Merge pull request #8 from petems/test_adam_with_no_config

Fixes issues with no config defined