No edit command for now. Added a message for invalid commands on console. Minor changes on mem.h and fat.c

Added mem module to Makefile and initialization of kernel memory on kernel C function. Added FAT function to load a file on memory (kernel data memory)

Added ext2 modules because FAT is to uggly. Experimental ext2 implementation. Structures required in ext2 filesystem defined

Change FAT32 to FAT16, so the boot record structure is changed to (because the extended boot record is for FAT16 now)

Add hard disk support trow ATA disk. It will use PIO polling mode (for now). In the future will use polling/IRQ to multitasking. Its implemented CHS mode so the acces is not through a filesystem but direct access (just in this module, because its the hard drive driver)

The kernel catch the multiboot info structure when it boots. With this we know the boundaries of the available memory. The definition of the structure is in def.h and in boot.s pass as a pointers to C kernel function

Implemented the PIT driver. this driver manage the kernel clock. The sleep function is implemented too.

implemented a IO module. It only contains one function (for now): getc. This function reads a char from STDIN (keyboard buffer) if the user press the enter key. This function use read_keyboard_buffer function implemented in keyboard.h (this is the interface to read the keyboard buffer)

Finished the alpha keyboard driver. It can manage mayus and shift button. The keyboard module has a function that read from keyboard buffer. This function will be used to implement easy IO functions (like getc in C)