Update RoadMap

Signed-off-by: Dong Yuan <yuandong1222@gmail.com>
Add librados.h

Copy librados.h from ceph and removed unused functions

Now we just foucsed the following operations
1. Cluster handle create/distory
2. Cluster connect/disconnect
3. Pool operations: list/stat/create/remove
4. Ojbect operations: write/write_full/append/read/remove/truncate

Signed-off-by: Dong Yuan <yuandong1222@gmail.com>