message: Derive common traits on Mesh
  Resolves
diff: @@ -992,6 +992,7 @@ impl Drawable for Image {
  }
  /// 2D polygon mesh
  +#[derive(Debug, Clone, PartialEq)]
  pub struct Mesh {
  buffer: gfx::handle::Buffer<gfx_device_gl::Resources, Vertex>,
  slice: gfx::Slice<gfx_device_gl::Resources>,
  