war on -Werror, part 8: more informals.

General guide: if the parameter name and its typings
match almost exactly, the name goes away.
Otherwise, it's commented out to allow for some
documentation.

src/ScreenOptionsMemoryCard.cpp

@@ -187,7 +187,7 @@ void ScreenOptionsMemoryCard::SelectRowWithMemoryCard( const RString &sOsMountPo
 }
 
 static LocalizedString ERROR_MOUNTING_CARD ("ScreenOptionsMemoryCard", "Error mounting card: %s" );
-void ScreenOptionsMemoryCard::ProcessMenuStart( const InputEventPlus &input )
+void ScreenOptionsMemoryCard::ProcessMenuStart( const InputEventPlus & )
 {
 	if( IsTransitioning() )
 		return;