Bunch of improvements in the device, memory and MMU handling.
Re-worked the NEAT 286 chipset (ported from VARCem).
Re-worked the ATI 28800 a bit, added Sierra SC1502x ramdac to VGA Wonder XL (Compaq) since it supports such.
Top 384K memory handling improvements (256K top memory too)
Added MCA version of MPU-401 (not tested much, however).
Re-worked the SCAT 286 chipset.
Several bug fixes;
Preliminar addition of the SDL 2 renderer (does not yet work correctly in full screen mode);
SCSI devices no longer have configurable LUN's (this matches the configurability of real SCSI devices);
SCSI LUN's are now handed by the device's handler;
Removed all unused strings;
Removed some unused code files;
Significantly rewrote the bus mouse emulation.
Fixes to various hard disk controllers;
Added the Packard Bell PB640;
Fixed the InPort mouse emulation - now it works correctly on Windows NT 3.1;
Removed the status window and the associated variables;
Completely removed the Green B 486 machine;
Fixed the MDSI Genius;
Fixed the single-sided 5.25" floppy drive;
Ported a CPU-related commit from VARCem.
Extensively cleaned up and changed the CD-ROM code;
Removed CD-ROM IOCTTL (it was causing performance and stability issues);
Turned a lot of things into device_t's;
Added the PS/1 Model 2011 XTA and standalone XTA hard disk controllers, ported from Varcem;
Numerous FDC fixes for the PS/1 Model 2121;
NVR changes ported from Varcem;
The PCap code no longer requires libpcap to be compiled;
Numerous fixes to various SCSI controllers;
Updated NukedOPL to 1.8;
Fixes to OpenAL initialization and closing, should give less Audio issues now;
Revorked parts of the common (S)VGA code (also based on code from QEMU);
Removed the Removable SCSI hard disks (they were a never finished experiment so there was no need to keep them there);
Cleaned up the SCSI hard disk and Iomega ZIP code (but more cleanups of that are coming in the future);
In some occasions (IDE hard disks in multiple sector mode and SCSI hard disks) the status bar icon is no longer updated, should improve performance a bit;
Redid the way the tertiary and quaternary IDE controllers are configured (and they are now device_t's);
Extensively reworked the IDE code and fixed quite a few bugs;
Fixes to XT MFM, AT MFM, and AT ESDI code;
Some changes to XTIDE and MCA ESDI code;
Some fixes to the CD-ROM image handler.
Reduced sound gain options to one (because the per-source gain does not work right);
Added the Diamond SpeedStar PRO (CL-GD 5428), per patch from TheCollector1995.
The UMC UM8669F's reset function now make sure the FDC pointer does not get lost, should fix the segmentation fault on reset;
The Winbond W83877F's reset function now zeroes the registers before setting the default values.
The settings dialog now keeps track of MFM/XTIDE/ESDI/IDE channels and SCSI ID's and LUN's;
The IBM PS/2 Model 50 now installs a Model 80-style memory expansion card (MCA ID FCFF) when more than 2 MB RAM is selected, and now supports a maximum of 10 MB RAM.
Merged floppy.c and fdd.c and renamed floppy_*.c (the floppy image format handlers) to fdd_*.c;
Reading the AT or PS/2 keyboard controller status no longer clears the transmit timeout bit, fixes error 8601 (mouse error) on the IBM PS/2 Model 80;
MMU translate and DMA physical reads and writes now go through _mem_exec instead of directly to ram[], should fix the last remaining problems with remapped mappings;
Implemented the Sound gain dialog;
Added the resource for the "New floppy image" dialog and the needed functions for the functionality of exporting the currently mounted floppy image as 86F, both of which should be finished in the next commit;
Applied the CD-ROM fixes from the PCem commit;
Added the "Keep ratio" option for full screen stretch.
Re-worked the system pathnames (pc.c), renamed cfg_path to usr_path.
Other small things here and there.
Logitech bus mouse re-worked, should be OK now.
