Turned the char arrays in gameport.h into const char pointers;
The makefile no longer links in the (unfinished) PIIX4 emulation code (which is currently not used by anything even in the Dev branch).
IBM.H is gone, video stuff re-organized. Keyboard stuff reorganized.
Machines that have their own video, mouse and/or keyboard now have all this in their machine file.
Fixed and other cleanups here and there.
The Settings dialog now correctly filters devices by bus;
Split the dual VLB/PCI graphics cards into VLB and PCI versions;
Device filtering is now done using the new device_is_valid() call that compares device flags to machine flags;
Moved the NCR-based SCSI controllers to the main branch;
Moved the NE1000 to the dev branch until it's finished.
