Add module support to oil

Patch adds module support for (as of now) the following oil commands
* ```oil g controller```
* ```oil g model```
* ```oil g migration```
* ```oil g task```
* ```oil g views```

Furthermore, a new oil generate command ```oil g module``` is added to allow for creating modules with an additional option ```--folders=``` to automatically create specified folders.
Example usage

```
oil g module portfolio --folders=classes/controller,classes/model,config,lang
```

```oil g module``` also checks whether the app has configured multiple module paths as in config ```module_paths``` and gives a nice select prompt if there's more than one module path defined

Would love to see the PR accepted and merged into 1.8, but maybe there's no more need for it before Fuel v2 will be released.