[feature] Loading images from resources

[Nearga]

1. If value = "/Resources/Image/MyImage.png" (or whatever), it would be loaded and
   rendered.
2. If string is null, it would load temporary image
   (Constants.RESOURCE_IMAGE_EMPTY_PRODUCT =
   "/Resources/Image/DummyImage.png")

[Nearga]

Actually, you can also add to line 36.

        imageUri = String.IsNullOrEmpty(value as string) 
                    ? new Uri(Constants.RESOURCE_IMAGE_EMPTY_PRODUCT, UriKind.Relative) 
                    : new Uri((string)value);

For handling, if string is empty.

[Nearga]

Fixed usage of imageUri.Scheme for Relative cases (somehow, sometimes it
throws exception, now it is fixed).

[Nearga]

Cleaner code.