Storage object comparison operator

[hameerabbasi]

          But we don't really have a string representation of a format or a format property in the `Tensor` class. So there's no way checking if the current format is e.g. `csf` and I would prefer to avoid parsing Julia's `_obj` repr if it matches some regex - it appears counterproductive to me.

Originally posted by @mtsokol in #45 (comment)

[willow-ahrens]

We could recursively walk the levels creating copies and error if we reach a level where the formats don't match. Even if we had a string format thing, we would still need to recurse down the levels to do the copy.

[willow-ahrens]

Perhaps typeof should suffice

[willow-ahrens]

I think this is a dup of #13, and for now we can use typeof until we merge #19