dump utilities, then header conversion

I think it might be best to split off the header conversion into a separate version, with 1.7 now tightly focused on the new dump capabilities. The (new) 1.8 would then deal almost entirely with header conversion.

Getting 1.7 with the new dump capabilities into beta and shipped will be helpful for both Norm and I, as we are managing moderately large Arks. Also, I want these utilities stable well before releasing header conversion.