Remove example.cfg as it is no longer useful.

With the addition of the declarative settings classes the defaults are
set to the equivalent of passing in example.cfg in the first place.
Rename WorkerCollection to WorkerSet.
Flesh out the printing of a Config instance.
Removed a wayward print statement used in debugging.
Fix bug the csv Setting type.

The order of which-value-was-being-split-by-what was reversed so we
always ended up with "," as the queue to operate on.