Added the 3Com 3C503 Network card;

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.

src/mouse.h

@@ -73,6 +73,8 @@ extern int	mouse_get_type(int mouse);
 extern int	mouse_get_ndev(void);
 extern int	mouse_get_buttons(void);
 
+extern void	mouse_clear_data(void *priv);
+
 #ifdef __cplusplus
 }
 #endif