Improvements to restoring stalled netgames

- The waiting message is now always cleared, regardless if it needed to
be in the first place. It's a rather simple for-loop so I doubt it
matters.
- Nodes are also cleared from the list if they catch up while other
nodes are still behind.
- "lastglobalrecvtime" is now bumped after the waiting loop if a tic was
successful, rather then bumping it every time a packet was received. It
appears that you can receive a packet before the game knows it stalled,
thus stalling it anyway.
- Instead of comparing the nettics to the local node, all nodes are
tested against gametic+counts (the real reason why the game has
stopped).
- More then one node can be marked as late at any one time.
- In a packet-server game, the arbitrator is now assumed slow, rather
then testing it. There is no point, seeing as we already know the game
has stalled because of it.