15 May 2002: changed value of dipwidth in period_11.m (1.9 --> 1.85) to 
avoid error condition.

20 June 2002: plot square root of aperiodicity ratio, rather than ratio 
itself

1 June 2003: new version of YIN.  The implementation is improved (faster, 
more robust, bugs corrected).  YIN now processes files a chunk at a 
time, so it can handle larger files.

28 July 2003: bug fixes.

1 Sept 2003: put sf routines in yin/private/.

16 Sept 2003: bug fix.

17 Sept 2003: bug fix.

22 Sept 2003: bug fix (rdiff_inplace.c).  Mex functions must be
recompiled for Windows.  Added option 'shift' to allow windows to
shift left, right, or symmetrically.

30 Sept 2003: changed definition of 'thresh' parameter to match 
the value actually used in algorithm (threshold for min of difference
function).  Old and new definitions differ by a factor of two.  Old 
default was 0.1, new is 0.2 (behavior is the same).  

3 Oct 2003:
- Fixed a bug that increased error probability at buffer edge.
- Fixed a weakness in the search for minimum that increased the
 likelihood of a 'too low' error.
- New parameter 'relflag'.  If 0 the threshold is absolute, if
 ~0 the threshold is relative to the global minimum of the difference
 function.  Default is 1.  This changes the semantics of 'thresh'.
- Default of 'thresh' is now 0.1.
- Windows: mex files must be recompiled!



