Adding support for Download builder

Closes #789. As discussed in dev mailing list and under issue #789.

I don't know if we use all builder subclasses as inner classes or external classes. Ideas?

After all comments, I can write some docs and improve tests for bytearray and inputstream.
:D cool
Em 11/09/2014 10:14, "Otávio Garcia" <notifications@github.com> escreveu:

> In
> vraptor-core/src/test/java/br/com/caelum/vraptor/observer/download/FileDownloadTest.java:
>
> >  public class FileDownloadTest {
> >
> > +	@Rule
> > +	public ExpectedException thrown = ExpectedException.none();
> > +
> > +	@Rule
> > +	public TemporaryFolder folder = new TemporaryFolder();
> > +
>
> There are some places in our code that creates tmpfile, and we can use
> this rule to remove all files after test finish. This rule is awesome.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/caelum/vraptor4/pull/791/files#r17419439>.
>