Fixed bugs about kheap, paging and ordered list

Furthermore, added Heap kernel driver code
for both allocation and deallocation
free() does not works yet:
`ASSERTION-FAILED(head->magic == HEAP_MAGIC) at kheap.c:261`

kernel/drivers/ordered_list.c

@@ -1,4 +1,7 @@
 #include "ordered_list.h"
+#include "kheap.h"
+#include "../cpu/assert.h"
+#include "../libc/string.h"
 
 uint8_t standard_lessthan_predicate(type_t a, type_t b) {
     if(a < b)