I made an attempt to disambiguate them
in 39d179afb948aa0700e54ccd4c8b129473b90498.  Basically, `queryForNames`
returns you a list of all names (think of them as service types) that have
been registered.  `queryForInstances` can then use that output (a name) to
return all instances of that name that have been registered.

It took me a while to get things sorted out mentally too.  There are
actually several levels of nesting/grouping in the Curator registry.
 First, this is the instance class (the `T` in `ServiceInstance<T>`).
 Under that is the service `name`.  Then there are instances of each
service.  I emulate this in RSR by creating a tag for each of `T` and
`name`.  There is a chance they could collide, but you'd have to be a
special breed of numbskull to do that.