Correct locked shapes' rotation after corner drag

When using the new (on 0.9.25) corner-drag option for creating
a new shape, "shape-locked" (1:1 aspect ratio) shapes -- square
and octagon -- would only rotate in a few positions, based on the
angle of ther vertices.

Corrected this, with no apparent adverse effect on other shapes,
in either drag mode (classic "from-center", and new "from-corner").

Also, removed extranous whitespace before EOLs in src/tuxpaint.c.

src/tuxpaint.c

@@ -22,7 +22,7 @@
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   (See COPYING.txt)
 
-  June 14, 2002 - October 15, 2020
+  June 14, 2002 - November 10, 2020
 */
 
 
@@ -13271,6 +13271,10 @@ static int shape_rotation(int ctr_x, int ctr_y, int ox, int oy)
   else if (shape_radius < 100)
     deg = ((deg - 7) / 15) * 15;
 
+  /* Disabled b/c it adversely affected shape_locked shapes (square & octagon)
+     with corner-dragged shapes; disabling doesn't seem to cause problems
+     with any shape, in either drag mode... -bjk 2020-11-10 */
+/*
   if (shape_locked[cur_shape])
     {
       int angle_skip;
@@ -13278,6 +13282,7 @@ static int shape_rotation(int ctr_x, int ctr_y, int ox, int oy)
       angle_skip = 360 / shape_sides[cur_shape];
       deg = deg % angle_skip;
     }
+*/
 
   return (deg);
 }