Convert Windows-1252 charset to UTF-8

Windows-1252, seriously?
(this hard-to-detect weirdo charset really makes some problems with some
cmdline text-tool)

contrib/clipper/clipper.cpp

@@ -26,7 +26,7 @@
 * Paper no. DETC2005-85513 pp. 565-575                                         *
 * ASME 2005 International Design Engineering Technical Conferences             *
 * and Computers and Information in Engineering Conference (IDETC/CIE2005)      *
-* September 24–28, 2005 , Long Beach, California, USA                          *
+* September 24–28, 2005 , Long Beach, California, USA                          *
 * http://www.me.berkeley.edu/~mcmains/pubs/DAC05OffsetPolygon.pdf              *
 *                                                                              *
 *******************************************************************************/

contrib/clipper/clipper.hpp

@@ -26,7 +26,7 @@
 * Paper no. DETC2005-85513 pp. 565-575                                         *
 * ASME 2005 International Design Engineering Technical Conferences             *
 * and Computers and Information in Engineering Conference (IDETC/CIE2005)      *
-* September 24–28, 2005 , Long Beach, California, USA                          *
+* September 24–28, 2005 , Long Beach, California, USA                          *
 * http://www.me.berkeley.edu/~mcmains/pubs/DAC05OffsetPolygon.pdf              *
 *                                                                              *
 *******************************************************************************/