Add `file_from_config` method for building config.

+ Add a new method that creates the config from three arrays
+ Each array for `input`, `filter`, and `output` can be hashes or
strings
+ Add a spec for this new method
Update attributes and recipe to use new config method.

+ Update config to use separate arrays
+ Update recipe to use new `file_from_config` method
+ Fix some whitespace in the integration tests
Update `Vagrantfile` to use new config layout.