Rewrote the networking system so SMP is working again.
convert foodprep from createmealpacket->datablockpacket properly, createmealpacket is no longer needed
streamline knapping by doing nothing if stacksize<=1
removed references to sleeptimer to prevent server crashes on first hourly tick
Rolling back to 1.7.2 (1.7.10 was too unstable), all changes are still present and working
(use the 1.7.10 branch to upgrade again - may require tweaking)