Introduce Ryu RFProxy implementation

ryu_rfproxy/: created to contain ryu rfproxy.
ryu_rfproxy/rfproxy_v1_2.py:
        - main app
        - _eth_type extracted correctly
        - removed tabs
ryu_rfproxy/rfofmsg.py:
        - mirrors pox rfproxy rfofmsg
        - added ldp config
        - bgp config matches tcp port
        - dc drop all now drops packets rather than
            sending to controller
        - uses single table for config
        - flow priorities fixed
rflib/defs.py:
        - merge ryu defs changes
        - added OFP_DEFAULT_PRIORITY (exists in ofv1.0 not ofv1.2)
rflib/ipc/ryu_MongoIPC:
        - similar to POX MongoIPC, but works with Ryu's event manager
Added RouteMod support
Add IPv6 Support

Convert IPv6 routemod matches to OF1.2 messages
Move RFProxy into subdirectory

Signed-off-by: Joe Stringer <joestringernz@gmail.com>
Set priority to lowest by default

Signed-off-by: Joe Stringer <joestringernz@gmail.com>
Minor formatting fixes

Signed-off-by: Joe Stringer <joestringernz@gmail.com>
Log RouteMod TLVs that we cannot parse

Signed-off-by: Joe Stringer <joestringernz@gmail.com>
Add gevent wrapper to work with rflib.MongoIPC

Signed-off-by: Joe Stringer <joestringernz@gmail.com>
Do not import invalid module

Signed-off-by: Joe Stringer <joestringernz@gmail.com>
Don't attempt to dereference "None" datapath

Signed-off-by: Joe Stringer <joestringernz@gmail.com>