Hopefully other users might have better luck than me :-/

Rewrite the algorithm to prefer entries which can be directly moved
into their target slots; this should reduce the number of descriptors
in most cases (although not necessarily *all* cases.)

Try to clean up the code some while we're at it... the code is
confusing enough as it is.

The old code could fail to coalesce backwards in the case where a
range is totally obliterated.  For now, just scan the whole list.

There are plenty of systems out there with more than 64 e820
descriptors.  The hard-coded limit is only used during initialization,
so we might as well go nuts.

Print minimal message while loading.

Use the syslinux_memmap data structure for the free memory list.  This
means we get range coalescing; this sometimes generates lists that are
vastly shorter than without range coalescing.

Handle the case of an upward move when there is something in the way.
This happens when loading an SDI image.

ext2/3 directory blocks are *not* ended with inode == 0; that reflects
a deleted block (like 0xe5 in FAT.)  Directory blocks are ended by
directory block exhaustion; the last block is simply made as large as
the whole directory block.

COM32 module to load a Microsoft System Deployment Image (SDI) file.