RestTemplate converters set in @Rest

[pyricau]

See #206.

We're updating AndroidAnnotations to work with RestTemplate 1.0.0.RELEASE. This means that we must accomodate to the changes. One of these changes is that RestTemplate default constructor now comes with no converters. So we must reflect that on the API, by forcing the user to explicitly declare the converters to use, because the most common case is to actually use converters.

@Rest now holds a new converters() parameter on which one can define the converter classes to use. The value() parameter has been renamed to rootUrl() and is still optional.

Usage example:

@Rest(rootUrl = "http://company.com/ajax/services", converters = { MappingJacksonHttpMessageConverter.class })
public interface MyService {
}