In preparation for v1 this commits adds a few options so we can get
start debugging the protocol for v1.
This options are:
1) Datasync: If enabled it will send datasync messages
2) V1Messages: If enabled it will send v1 messages (just adding a
signature to the message)
3) Disable discovery topic: If enabled it will stop listening/publishing
on the discovery topic. You will be able to receive messages only from
clients who have this enabled as well.
If any of this option is on, it will only be compatitle with builds >=
this one. A logout is required for any change to take effect.
All this options will be removed before v1, they are there just to make
it easier for us to test and find potential issues.
Signed-off-by: Andrea Maria Piana <andrea.maria.piana@gmail.com>