This should work with blocks bigger than that, but my linux system
only supports up to 4 KiB, so I cannot test this.
This allows getting rid of forced block size in mkfs and let the
program select appropriately sized blocks.
Bochs int 0x10 seems to scrap full ebp and top bits in some
registers. I now save all 32-bit registers on call frame. Also
ebp is across all int 0x10 calls.
Framebuffer information is no longer hard coded into bootloader.
Kernel can define framebuffer info structure in its memory which is
used for finding proper video mode.