Implement handshake protocol

[matjazv]

Description

When establishing a new connection with a peer, a connection must be accepted only if some conditions are true:

• chainID
• networkVersion

A peer should also send info if it's addresses can be advertised to other peers in the network or not.

• advertiseAddress

Acceptance Criteria

• Only valid connections from other peers are accepted.
• If peer sets advertiseAddress to false it's address is not passed to the other peers.
• All new code is unit tested.