message: Added pixel_type typedef to Image
  This is useful to for example access the PixelType of a particular image when calling the zeros(...) function.
diff: @@ -43,6 +43,8 @@ template <class PixelType>
  class Image
  {
  public:
  + using pixel_type = PixelType;
  +
  Image() = default;
  // Initialises with all zeros. This is a bit of an overhead. We probably have to use unique_ptr or a raw
  