Adding replication using the "_replicator" database

[carlosduclos]

Starting with 1.2.0 CouchDB added a new system database called "_replicator" to handle replications jobs.

Replications are now created as entries on that database and the server will schedule and perform the replication accordingly. Entries in the "_replicator" db will be updated.

This means that replication now is a completely asynchronous job that is not guaranteed to run right after the replication was started.

This commit adds three new object with three object to handle this new type of replication:

• replication.enable: To enable the replication of a database.
• replication.query: To query the status of a replication job.
• replication.disable: To disable the replication of a database.

More information on this type of replication can be found:

• https://wiki.apache.org/couchdb/Replication#from_1.2.0_onward
• http://guide.couchdb.org/draft/replication.html
• https://gist.github.com/fdmanana/832610

Refers to issue #349.

[carlosduclos]

Merged on apache/couchdb-nano