Builder mode setter support

I removed the void return type check for setter resolution, because you can not have two methods with the same signature (one void and one that returns something).
Nothing changed overall, only that now I van use builder style setters to simplify my code.

```java
public class CollectionHolder {
    private String[] array;
    private Collection<String> collection;

    public CollectionHolder setArray(String[] array) {
        this.array = array;
        return this;
    }
}
```
Merge pull request #190 from mstipanov/builder_setter_support

Builder mode setter support