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/get-response.xml

@@ -1,6 +1,6 @@
 <?xml version='1.0' encoding='UTF-8' standalone='no'?>
 <?xml-stylesheet href="dialog.xsl" type="text/xsl"?>
-<dialog skin='dark' defbtn='okay'>
+<dialog defbtn='okay'>
 	<field name='response' type='text' top='34' left='88' width='75' height='16'/>
 	<text name='prompt' size='large' top='6' left='55' width='141' height='16'>You respond:</text>
 	<pict name='pic' type='dlog' num='16' top='8' left='8'/>