Moved fs.c and mp.c into xng and fs.h and mp.h into include
Moved kbd.c in xng and kbd.h in include
Moved file.c in xng and file.h in include
[REFACTOR] Moved spinlock.c under xng and spinlock.h under include
[REFACTOR] Moved picirq.c into xng
[REFACTOR] Moved x86.h into include
[REFACTOR] Moved bootmain.c into xng
[REFACTOR] Moved stat.h in include and main.c in xng
[REFACTOR] Moved vm.c into xng
[REFACTOR] Moved timer.c into xng
[REFACTOR] Moved bio.c, exec.c and console.c into xng.
[REFACTOR] Moved ide.c, ioapic.c and kalloc.c into xng
[REFACTOR] Moved lapic.c, log.c, pipe.c and proc.c into xng
[REFACTOR] Moved string.c and swtch.S in xng, and modified the makefile to output the perl's script file into xng
[REFACTOR] Moved trap.c and trapasm.S into xng
[REFACTOR] Moved uart.c into xng
[REFACTOR] Moved sysproc.c into xng
[REFACTOR] Moved sysfile.c into xng
[REFACTOR] Moved syscall.h into include and syscall.c into xng.

This marks a checkpoint, where all the kernel files are inside
the xng folder.