Various fixes and improvements.

- fixed bug that caused IDLE to panic (irq hook inconsistency);
- kprintf() now accepts multiple arguments; moved to utility.c;
- prepare_shutdown() signals system processes with SIGKSTOP;
- phys_fill() renamed to phys_memset(), argument order changed;
- kmemset() removed in favor of phys_kmemset();
- kstrncpy() removed in favor of phys_copy();
- katoi, kstrncmp replaced by normal library procedure again;
- rm_irq_handler() interface changed (simply pass hook pointer);

kernel/type.h

@@ -3,11 +3,6 @@
 
 typedef _PROTOTYPE( void task_t, (void) );
 
-/* Type accepted by kprintf(). This is a hack to accept both integers and
- * char pointers in the same argument. 
- */
-typedef long karg_t;			/* use largest type here */
-
 /* Process table and system property related types. */ 
 typedef int proc_nr_t;			/* process table entry number */
 typedef short sys_id_t;			/* system process index */