FDC changes :

- Seperated disk and disk drive emulation
- Support more drive types - 5.25" dual RPM, 3.5" DD, 3.5" HD, 3.5" HD 3-Mode
- Support drive swapping (FDC37c665 only)
- Support FDC FIFO
- Support other FDC 'enhanced mode' behaviour
- Support IBM XDF format images
- Formatting now formats both tracks, and uses correct 'fill' byte
- Various other improvements

Many of these changes provided by Battler

src/fdd.h

@@ -0,0 +1,12 @@
+#define SEEK_RECALIBRATE -999
+void fdd_seek(int drive, int track_diff);
+int fdd_track0(int drive);
+int fdd_getrpm(int drive);
+void fdd_set_densel(int densel);
+int fdd_can_read_medium(int drive);
+int fdd_doublestep_40(int drive);
+
+void fdd_set_type(int drive, int type);
+int fdd_get_type(int drive);
+
+extern int fdd_swap;