Improved passing of scan codes to the emulated keyboards;

Fixed Sound Blaster 16 and earlier CD-ROM volume registers (and made them no longer default to 0);
Serial mouse now resets the FIFO before sending the ID, fixes mouse detection after clipping and moving the mouse;
Rewritten CD-ROM and SCSI disk Mode Select handling and changed things regarding Mode Sense as well, also fixes emulator segmentation faults when anything attempts to do a Mode Select;
Fixed the Microsoft InPort mouse emulation (used the Bochs code as reference for the polling/state update code), now it actually moves;
The PCjr initialization now sets the XT scan code table, makes the keyboard actually work on the PCjr again;
Several bugfixes regarding the Read CD commands, fixes CD Audio in digital mode on Windows ME;
Finally properly fixed the regular CD Audio MSF/LBA conversion mess;
Applied all applicable PCem commits.

src/sound/snd_sb_dsp.h

@@ -62,6 +62,8 @@ typedef struct sb_dsp_t
         
         int64_t wb_time, wb_full;
 
+	int busy_count;
+
         int record_pos_read;
         int record_pos_write;
         int16_t record_buffer[0xFFFF];