Added code to support getting interrupts from the PIC. Can now get some data from the keyboard, however, it's not quite working yet.

kernel/interrupt_handler.c

@@ -1,8 +1,10 @@
 #include "../includes/interrupt_handler.h"
 #include "../includes/serial.h"
+#include "../includes/screen.h"
 
 void interrupt_handler(struct isr_state stack)
 {
+	write_to_com(COM1_PORT, int_to_string(stack.int_no, 10));
 	write_to_com(COM1_PORT, "Divide by zero detected!\n");
 	write_to_com(COM1_PORT, "Halting system!\n");
 	asm("cli");