- reinstalled priority changing, now in sched() and unready()
- reinstalled check on message buffer in sys_call()
- reinstalled check in send masks in sys_call()
- changed do_fork() to get new privilege structure for SYS_PROCs
- removed some processes from boot image---will be dynamically started later
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.
