(#30) - correctly implement _uuids
(#32) - fix allDbs()
(#37) - gitignore and app.del -> app.delete

Adds a standard Node .gitignore and also
renames app.del to app.delete, since Express
was giving us warnings about that.
(#35) - fix binary attachments

Every incoming req.body was being coerced to utf-8,
which is not correct for binary attachments.
This adds an extra property, req.rawBody, which
can be used for attachments.
(#39) - implement replication history
(#41) - return correct error code in changes
(#43) - implement live replication cancelling