Warn if Makefile is out of date
Don't rebuild version.o if nothing has changed
Move msp retransmit time to #define'd const
Remember specified rate limit
Only use the best rtt calculation once per ack
Move rate limit code to separate file
Don't process MDP packets if the local address is invalid
Don't busy wait for forked processes to terminate
Remove respawn_on_crash behaviour, we aren't using or testing it