Create a dedicated "nautilus" branch?

[LenzGr]

As the iSCSI management functionality of Ceph Dashboard is tightly coupled with ceph-iscsi's features, I think it would make sense to have git branches for ceph-iscsi that correlate with the Ceph version they have been developed against and tested with. I'd like to suggest that we branch off the current 3.x version in the master branch into a "nautilus" branch and bump up the version number in the master branch accordingly.