08/17/2012  Big changes: replaced the algorithm of Valdes (PASP 107, 1119, 1995)
               with that of Tabur (PASJ 24, 189, 2007).  New method is more
               robust, can be quicker for large numbers of objects.
               There's one new input argument (min_req_pairs), and the
               default value of another argument (halt_sigma) has
               been changed.
            Modified values in selftest.pl slightly, even though using
               the same tests.

12/05/2011  New arguments to allow user to specify rotation
               The "rotangle=" and "rottol=" arguments allow user
                   to specify an allowed range of rotation angles
                   between the two sets of coordinates

11/30/2010  Added Unix-style man page, "install" target

6/26/2010   Very minor changes
                Now print elements of TRANS as %15.9e instead of %15.9f
                   should increase accuracy when elements have small values
                Added information in debug printf in "atpmatch.c"
                   now print the ratio of triangle scales when a match is found
                
6/11/2008   Bug fix in "apply_match.c"
                added extra %s in sscanf statement

10/25/2003  Small change to "project_coords" program:
                new option "asec" prints (xi, eta) in arcsec, not radians

5/19/2003   Small fix to "apply_match" program:
                now handle coordinates near celestial poles properly

10/23/2002  Small bug fixes to avoid assertion failures: 
                match.c and atpmatch.c

6/19/2002   Enhancements, code supplied by John Blakeslee:
                new routine, atCalcRMS, calculates "sx" and "sy" for
                all matching items in each direction, using 1 iteration
                of 3-sigma clipping

12/31/2001  More enhancements, suggested by John Blakeslee:
                a. identity [xsh=] [ysh=] option
                b. intrans= option, so user can specify exactly the
                     expected TRANS
            Several small bug fixes, thanks to John and Andrew Bennett.

12/14/2001  A number of enhancements, suggested by John Blakeslee.
            Also fixed a bug in handling the "id" columns.

6/28/2001   Fixed minor bug in "project_coords.c", around line 300.
            The "sscanf" call used to read in data had only 10 %s
				in the format string; it should have had 20 of them.
				It caused the program to discard any data after the
				10'th column in the input file.  

