aubio: added HEAD source

Indeed they do. :)

> On 6 Nov 2014, at 17:30, Dominyk Tiller <notifications@github.com> wrote:
> 
> In Library/Formula/aubio.rb:
> 
> > @@ -20,6 +22,12 @@ class Aubio < Formula
> >    depends_on 'pkg-config' => :build
> >    depends_on :libtool => :build
> >  
> > +  depends_on 'libav' => :optional
> > +  depends_on 'libsndfile' => :optional
> > +  depends_on 'libsamplerate' => :optional
> > +  depends_on 'fftw' => :optional
> > +  depends_on 'jack' => :optional
> Cool . I presume all the optional dependencies have pkg-config files to find?
> 
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