added method to chain input filters

Needed a clean way to chain input filters together 
Done as per request


On Tue, Jul 15, 2014 at 1:59 PM, Daniel Gimenes <notifications@github.com>
wrote:

> In tests/ZendTest/InputFilter/InputFilterTest.php:
>
> > @@ -115,4 +115,5 @@ public function testCanUseContextPassedToInputFilter()
> >
> >          $this->filter->isValid($context);
> >      }
> > +
>
> Remove this line.
>
> —
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> <https://github.com/zendframework/zf2/pull/6431/files#r14932014>.
>