replication using _changes API

[Adam Kocoloski]

I had some time to work on a replicator that queries _changes instead  
of _all_docs_by_seq today.  The first question that came to my mind  
was how to put a spigot on the firehose.  If I call _changes without a  
"since" qs parameter on a 10M document DB I'm going to get 10M chunks  
of output back.

I thought I might be able to control the flow at the TCP socket level  
using the inets HTTP client's {stream,{self,once}} option.  I still  
think this would be an elegant option if I can get it to work, but my  
early tests show that all the chunks still show up immediately in the  
calling process regardless of whether I stream to self or {self,once}.

All for now, Adam