Parameters as target

This release only includes a single change: all annotation can now also be applied to method and constructor parameters:

public class Book {
    private String isbn
	
    public Book(@ISBN String isbn) {
        this.isbn = isbn;
    }
} 

In order for this to work you need a framework that takes care of injecting the required validation code for you.

Thanks to @mehranroodsaz for raising this. See #26, #27.