New timer for NACKs to avoid retransmitting the same packet over and over
Update README.md
Merge pull request #103 from giavac/master

Update README.md for libevent-dev dependency
Clarified role of libevent in libwebsock (both optional)
Merge pull request #102 from meetecho/nack-timer

New timer for NACKs to avoid retransmitting the same packet over and over