Basic VM and other minor improvements.

Not complete, probably not fully debugged or optimized.

kernel/system/do_unused.c

@@ -10,7 +10,7 @@
 PUBLIC int do_unused(m)
 message *m;				/* pointer to request message */
 {
-  kprintf("SYSTEM: got unused request %d from %d", m->m_type, m->m_source);
+  kprintf("SYSTEM: got unused request %d from %d\n", m->m_type, m->m_source);
   return(EBADREQUEST);			/* illegal message type */
 }