Peer-id patch v3

Added new packet format P_DATA_V2, which includes peer-id. If server
supports, client sends all data packets in the new format. When data
packet arrives, server identifies peer by peer-id. If peer's ip/port has
changed, server assumes that client has floated, verifies HMAC and
updates ip/port in internal structs.

Fixed bug: If float happens after TLS renegotiation and there are no data packets between reneg and float, server will not recognize floated client.

Analysis:
We take decryption key from crypto_options, however it is set only after
first data packet has been received (ssl.c tls_pre_decrypt). So if no
data packets arrived between rekeying and float, HMAC verification will
fails.

Fix:
If we detect float, use key from tls_multi. We got it in same way as it
is done in ssl.c tls_pre_decrypt