Extensive rework of SCSI and ATAPI devices and numerous bug fixes and cleanups;

Extensive rework of CD-ROM image handling;
The settings save code now forces some devices' (SCSI disk, CD-ROM, etc.) pointers to NULL before resetting the machine - fixes segmentation faults after changing settings;
Added the NCR 53c825A and 53c875 SCSI controllers;
Fixed IDE/ATAPI DMA;
Slight changed to PCI IDE bus master operation.

src/pc.c

@@ -8,7 +8,7 @@
  *
  *		Main emulator module where most things are controlled.
  *
- * Version:	@(#)pc.c	1.0.87	2018/10/26
+ * Version:	@(#)pc.c	1.0.88	2018/10/28
  *
  * Authors:	Sarah Walker, <http://pcem-emulator.co.uk/>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -651,10 +651,8 @@ again2:
 
     keyboard_init();
     joystick_init();
-    video_init();
-    device_init();
 
-    timer_reset();
+    video_init();
 
     fdd_init();
 
@@ -662,9 +660,6 @@ again2:
 
     hdc_init(hdc_name);
 
-    pc_full_speed();
-    shadowbios = 0;
-
     return(1);
 }
 
@@ -723,6 +718,8 @@ pc_reset_hard_close(void)
 
     device_close_all();
 
+    scsi_device_close_all();
+
     midi_close();
 
     cdrom_close();
@@ -834,6 +831,8 @@ pc_reset_hard_init(void)
     pic_reset();
     cpu_cache_int_enabled = cpu_cache_ext_enabled = 0;
 
+    pc_full_speed();
+
     if (machines[machine].cpu[cpu_manufacturer].cpus[cpu_effective].cpu_type >= CPU_286)
 	setpitclock(machines[machine].cpu[cpu_manufacturer].cpus[cpu_effective].rspeed);
     else
@@ -908,6 +907,8 @@ pc_close(thread_t *ptr)
 
     device_close_all();
 
+    scsi_device_close_all();
+
     midi_close();
 
     network_close();