Builder class for the Report interface.

Hello,
The idea is to have a Builder class for the Report interface, so that the developer doesn't need to create a concrete class for each report.

Using this builder, your code will look something similar to this one when creating a report:
```
final Report report = new ReportBuilder()
		.withTemplate("report.jasper")
		.withData(dao.findAll())
		.with[...]
		.build();
```