Expose purge method.
0.0.47
Expose missingrevs() and revsdiff().
0.0.48
Expose replicate().
0.0.49
Expose replicate schema.
Move replicate() method.

And lazily stringify() the body document if a body document is present
and the content-type is application/json.
0.0.50
Remove Referer header for replicate().
Expose task type constants.
0.0.51