Doc: Boot

The Boot section defines the bootloader for PwnOS.

The bootloader is responsible for the following things:
- set the video mode
- enter Protected Mode
- set setup Local and I/O APICs
- start up all processors
- enable paging on all processors
- find the <Core> on disk
- read in the <Core> from disk
- set up necessary devices and <Core> modules
- enable tasking on all processors
- start interface process

Within the bootloader, the <MBR> (Master Boot Record) is responsible for loading the rest of the bootloader, setting the video mode, and entering Protected Mode.  The <MBR> code has an absolute maximum size of 510 bytes and a recommended maximum size of 446 bytes for the compatibility of having a partition table.
The <Boot> segment, which is loaded by the <MBR>, is responsible for everything else.  The entire bootloader must fit into 63 sectors, 31.5 KB.  This could be expanded to 126 sectors, 63 KB, with a 2nd level bootloader, but this will be avoided until determined necessary, because users may not want to have a partition dedicated to it.