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/config.h

@@ -53,7 +53,7 @@
  * a system server is notified and a copy of the buffer can be retrieved to 
  * display the message. The buffers size can safely be reduced.  
  */
-#define KMESS_BUF_SIZE   128   	
+#define KMESS_BUF_SIZE   256   	
 
 /* Buffer to gather randomness. This is used to generate a random stream by 
  * the MEMORY driver when reading from /dev/random.