With this change it is now possible to combine interface action events.
If an interface action is generated by netifd or mwan3 for example ifup,
ifdown, connectd or disconnected and this action is configured in the inteface
uci section, then the conntrack table is flushed by mwan3.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

- globals src_ip to none
 - ip route back to source
 - add mwan3rtmon
 - update version to 2.7

Signed-off-by: Chen Minqiang <ptpt52@gmail.com>