message: Add Deref{,Mut} impls to VertexBufferAny
diff: @@ -501,6 +501,22 @@ impl<T> From<Buffer<[T]>> for VertexBufferAny where T: Vertex + Copy + Send + 's
  }
  }
  +impl Deref for VertexBufferAny {
  + type Target = BufferAny;
  +
  + #[inline]
  + fn deref(&self) -> &BufferAny {
  + &self.buffer
  + }
  +}
  +
  +impl DerefMut for VertexBufferAny {
  + #[inline]
  + fn deref_mut(&mut self) -> &mut BufferAny {
  + &mut self.buffer
  + }
  +}
  +
  impl<'a> IntoVerticesSource<'a> for &'a VertexBufferAny {
  #[inline]
  fn into_vertices_source(self) -> VerticesSource<'a> {
  