Enhance included bios tables.

Moved floppy parameter table to its 0xefc7 location.
Define floppy base table as a struct.
Cleaned up definitions in romlayout.S
Fixed bug in handle_15c0 - wasn't clearing cf.
Clean up some post.c usages of bios tables.
diff --git a/src/config.h b/src/config.h
index feb8f27..a440201 100644
--- a/src/config.h
+++ b/src/config.h
@@ -13,4 +13,8 @@
 #define CONFIG_STACK_SEGMENT 0x00
 #define CONFIG_STACK_OFFSET  0xfffe
 
+#define CONFIG_MODEL_ID      0xFC
+#define CONFIG_SUBMODEL_ID   0x00
+#define CONFIG_BIOS_REVISION 0x01
+
 #endif // config.h