keep some processes mapped in always; direct message copying

where possible (no buffering); no more explicit vm checkranges
in kernel; new allocator for vm using avl tree without needing
remapping

kernel/proc.h

@@ -10,6 +10,7 @@
  * struct proc, be sure to change sconst.h to match.
  */
 #include <minix/com.h>
+#include <minix/portio.h>
 #include "const.h"
 #include "priv.h"