Removed the Mach64 ISA until someone finds a properly working BIOS;
Changed the Mach64 VLB to use the BIOS that actually works;
Moved the standalone TI CF62011 graphics card to the Dev branch until someone finds a BIOS for it;
Removed an accidental temporary change in win_dialog.c;
Reorganized the graphics card ID's to allow simplification of the MDA and VGA #define's in video.h;
Added a workaround for the TVGA8900D DAC sense, so the card is in color again.
Applied all applicable PCem commits;
The PS/1 and PS/2 machines now have the correct graphics cards - fixes the reference diskettes;
The open dialog code now changes directory to usr_path after the dialog is closed;
Disabled excess logging in the TI SVGA code.
