All dialogs now use default skin and foreground colour

(The attributes are still available in the schema though, and will not be removed.)

rsrc/dialogs/edit-mabil-summon.xml

@@ -1,6 +1,6 @@
 <?xml version='1.0' encoding='UTF-8' standalone='no'?>
 <?xml-stylesheet href="dialog.xsl" type="text/xsl"?>
-<dialog skin='light' defbtn='okay'>
+<dialog defbtn='okay'>
 	<pict type='dlog' num='16' top='8' left='8'/>
 	<text size='large' top='18' left='50' width='250' height='17'>Edit Monster Ability:</text>
 	<text top='52' left='10' width='100' height='16'>For monster:</text>