Order mismatch between styleTypes[] array and StyleIdx enum.

As, while reading scores, the index in styleTypes is used to access StylesData::values which are order by StyleIdx, styles between ST_noteBarDistance and ST_accidentalNoteDistance are read back into (and possibly written from) the wrong style.

Fixed by re-arranging the StyleIdx enum elements in style.h.

Incidentally, the StyleIdx enum and the styleTypes array have been re-formatted with the same spacing and comments to ease a side-by-side comparison.