getting back the old image for the mainmenu and to use it in about.cfg, too

that image is originally trunk/data/core/images/maps/wesnoth.png 2007-09-11T18:47:43Z!david@torangan.de

ATM both wesnoth.png and wesnoth-httt.jpg do use exactly the same "map
area" (as in images are identical beside the file format). Is this
wanted? If not, please change it...

data/_main.cfg

@@ -83,7 +83,7 @@
     recall_cost=20
     kill_experience=8
 
-    title="maps/wesnoth.png"
+    title="maps/mainmenu.png"
     logo="misc/logo.png"
     icon="wesnoth-icon.png"
     title_music="main_menu_new.ogg"

data/core/about.cfg

@@ -1,6 +1,6 @@
 #textdomain wesnoth
 [about]
-    images=maps/wesnoth.png,maps/wesnoth-httt.jpg
+    images=maps/mainmenu.png,maps/wesnoth-httt.jpg
 [/about]
 
 [about]