RFC: Reverse Array dims in no-copy conversion from Julia to Numpy

I've been working with image data and `PyPlot.imshow`, and finding that I have to munge the data more than I would like in order to get it to display:

```julia
PyPlot.imshow(permutedims(img.data, (3,2,1))
```

Digging into this, I found that reversing the dims and strides in the `PyObject` constructor let me display the image (more) directly with `PyPlot.imshow(img.data)`.

Now it's likely that this change would cause issues with other arrays being passed to Numpy, so I don't expect this to be merged.  But I'm wondering if a version which reverses the dims/strides can be made available somehow?