Draw timeouts on both sender and receiver + BUGS?

- a boolean value was added to sender and receiver state to
  indicate whether a packet was sent due to an expired timeout
- The timeout is rendered in the Flow diagram
- BUG detected? The receiver doesn't seem to handle timeouts
  correctly
- BUG detected? Should the sender resend packets after a timeout
  that was concurrent with the timeout of a previously resent
  packet?