Allow to define custom templates for inputs, errors, labels and hints.
Removing the `wrapControls` option.
Defining the `wrapperConfig` as a computed property.

This allows us to get the config easily, and makes the configuration
accessible to the templates.

For example:
```
<div {{bindAttr class="wrapperConfig.wrapperClass"}}>
my inputs
</div>
```
Including instructions about custom templates in the README.
Merge pull request #91 from diogomafra/custom-templates

Custom templates