- Shuffled the bios.S a bit to get a 32Kb of low memory for free.
- Added a management for it - lowmem.[ch]. This is needed for VESA
support.
- Since the VESA support is not there yet, the usual victim is builtins,
which are moved to use that heap instead of the on-fly DOS allocation
that may be not always safe.


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@672 7758b857-130e-0410-ab9c-d8735a528d18