tweaks: update some copyright years

Reflect the significant changes in painting and regex searching
in the copyright notices.

src/color.c

@@ -3,7 +3,7 @@
  *                                                                        *
  *   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,  *
  *   2010, 2011, 2013, 2014, 2015 Free Software Foundation, Inc.          *
- *   Copyright (C) 2014, 2015, 2016 Benno Schulenberg                     *
+ *   Copyright (C) 2014, 2015, 2016, 2017 Benno Schulenberg               *
  *                                                                        *
  *   GNU nano is free software: you can redistribute it and/or modify     *
  *   it under the terms of the GNU General Public License as published    *

src/nano.c

@@ -920,7 +920,7 @@ void version(void)
     printf(_(" GNU nano, version %s\n"), VERSION);
 #endif
     printf(" (C) 1999..2016 Free Software Foundation, Inc.\n");
-    printf(_(" (C) 2014..%s the contributors to nano\n"), "2016");
+    printf(_(" (C) 2014..%s the contributors to nano\n"), "2017");
     printf(
 	_(" Email: nano@nano-editor.org	Web: https://nano-editor.org/"));
     printf(_("\n Compiled options:"));

src/search.c

@@ -3,7 +3,7 @@
  *                                                                        *
  *   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,  *
  *   2008, 2009, 2010, 2011, 2013, 2014 Free Software Foundation, Inc.    *
- *   Copyright (C) 2015, 2016 Benno Schulenberg                           *
+ *   Copyright (C) 2015, 2016, 2017 Benno Schulenberg                     *
  *                                                                        *
  *   GNU nano is free software: you can redistribute it and/or modify     *
  *   it under the terms of the GNU General Public License as published    *

src/winio.c

@@ -3,7 +3,7 @@
  *                                                                        *
  *   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,  *
  *   2008, 2009, 2010, 2011, 2013, 2014 Free Software Foundation, Inc.    *
- *   Copyright (C) 2014, 2015, 2016 Benno Schulenberg                     *
+ *   Copyright (C) 2014, 2015, 2016, 2017 Benno Schulenberg               *
  *                                                                        *
  *   GNU nano is free software: you can redistribute it and/or modify     *
  *   it under the terms of the GNU General Public License as published    *