New configuration header file to include/ exclude functionality.
Extracted privileged features from struct proc and create new struct priv.
Renamed various system calls for readability.
Removed stop sequence when MINIX is shut down.
Disabled send mask checks --- to be replaced by proper mechanism.
Fixed bug relating to 'shutdown -x'.
Simplified clock accounting of realtime.
Updated Makefiles for mkdept script.
when lock timing is enabled in minix/config.h.
Added phys_zero() routine to klib386.s that zeroes a range of memory, and
added corresponding system call.
