doc: Organized into sections. Added zone/region and pool details.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
mon/OSDMonitor: fix POOL_OP_DELETE_SNAP early return

Cut&paste goof in 0e85074402cd02b292daadcb5b8e73ac1207d571.

Signed-off-by: Sage Weil <sage@inktank.com>
Merge git://github.com/ceph/ceph