Modify printk(), add idt, PIT
Modify Makefile for Ubuntu and Fedora grub2
I forget add README and kmain.c files, because they were change. I do in README just like myos -> simpleos, in kmain idt_st() function and PIT interrupt was started. Apologize for my carelessness...
Modify printk, Now the screen can scroll. In develop branch v0.0.4 tag I forget add lib/idt.c, I add here.
Sorry, I forget include/idt.h
Merge branch 'develop'. Now printk function, IDT, PIT was set.