Volume namespaces - fixes 771

Fixes #771.

Some temporary code is in place so this doesn't break the rest of the system.
While I'm hesitant to make our documentation too granular, in that we are writing for a technical audience, I suspect it may be worth putting an additional sentence in here just to explain the concept of a namespace for the benefit of people who aren't programmers. If I didn't come from a programming background, I'd probably be confused by this sentence.