Type check in VecMoran (or notebook) needs to be updated to account for new package structure

[ljwolf]

We need to update the vector autocorrelation typecheck to be a bit less prescriptive about where the "DistanceBand" weight is coming from. This was reported by @4rachelgreen in our gitter channel.

Ideally, we'd check the mathematical structure of the W and use any object that "works" sufficiently well in the function.