Dilated convolutions (#657)

* Add the dilation parameter.

* Restore the basic optimizer example.

* Dilation support in cudnn.

* Use the dilation parameter in the cpu backend.

* More dilation support.

* No support for dilation in transposed convolutions.

* Add dilation to a test.

* Remove a print.

* Helper function.

candle-examples/examples/musicgen/encodec_model.rs

@@ -278,6 +278,7 @@ impl EncodecConv1d {
                     padding: 0,
                     stride,
                     groups: 1,
+                    dilation: 1,
                 },
                 vb.pp("conv"),
             )?,
@@ -289,6 +290,7 @@ impl EncodecConv1d {
                     padding: 0,
                     stride,
                     groups: 1,
+                    dilation: 1,
                 },
                 vb.pp("conv"),
             )?,