Cast a blur effect on the WML message panel background...

...per Eleazar's suggestion

(Item 2 in the second part of
http://forums.wesnoth.org/viewtopic.php?p=423254#p423254).

data/gui/default/widget/panel_wml_message.cfg

@@ -6,6 +6,16 @@
 #define _GUI_BASE_NAME
 	"translucent65" #enddef
 
+#define __GUI_DIALOG_BLUR
+[pre_commit]
+
+	[blur]
+		depth = 5
+	[/blur]
+
+[/pre_commit]
+#enddef
+
 #define _GUI_RESOLUTION RESOLUTION BORDER_SIDE_1 BORDER_SIDE_2 OFFSET_SIDE_1 OFFSET_SIDE_2 OFFSET_TOTAL
 	[resolution]
 
@@ -20,6 +30,8 @@
 
 			[draw]
 
+				{__GUI_DIALOG_BLUR}
+
 				[image]
 					x = 0
 					y = 0