Set UNDEAD_PEOPLE as default tileset (CleverRaven#56)

Set UNDEAD_PEOPLE as default tileset

Co-authored-by: firestorm01x2 <firestorm01x2gmail.com>

src/options.cpp

@@ -1761,7 +1761,7 @@ void options_manager::add_options_graphics()
 
     add( "TILES", "graphics", translate_marker( "Choose tileset" ),
          translate_marker( "Choose the tileset you want to use." ),
-         build_tilesets_list(), "retrodays", COPT_CURSES_HIDE
+         build_tilesets_list(), "UNDEAD_PEOPLE", COPT_CURSES_HIDE
        ); // populate the options dynamically
 
     get_option( "TILES" ).setPrerequisite( "USE_TILES" );